Extended Analysis of Ar III and Ar IV

Mónica Raineri; Roberto E. Mejia Castellanos; Mario Gallardo; Jorge Reyna Almandos

doi:10.3390/atoms6030047

,

and

¹

Centro de Investigaciones Ópticas, M. B. Gonnet, P. O. Box 3, La Plata 1897, Argentina

²

Departamento de Materia Condensada, Escuela de Física, Universidad Nacional Autónoma de Honduras, Tegucigalpa 11101, Honduras

^*

Author to whom correspondence should be addressed.

Atoms2018, 6(3), 47;https://doi.org/10.3390/atoms6030047

This article belongs to the Special Issue Current Developments and Applications of Atomic Structure and Radiative Process Investigations

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Abstract

A pulsed discharge light source was used to study the two and three times ionized argon (Ar II, Ar III) spectra in the 480–6218 Å region. A set of 129 transitions of Ar III and 112 transitions of Ar IV were classified for the first time. We extended the analysis of Ar III to five new energy levels belonging to 3s²3p³4d, 3s²3p³5s odd configurations. For Ar IV, 10 new energy levels of the 3s²3p²3d and 3s²3p²4p even and odd configurations, respectively, are presented. For the prediction of energy levels, line transitions, and transition probabilities, relativistic Hartree–Fock calculations were used.

Keywords:

atomic spectra; energy levels; capillary pulsed-discharge; relativistic Hartree–Fock calculations

1. Introduction

Spectral analysis of several ions of argon has implications in different fields. In astrophysics [1,2,3], argon spectral lines are important in determining the chemical abundance of elements and estimating radiative transfer through stellar plasmas. Argon plasma sources are also applied in various fields of industry and research [4,5,6,7].

A compilation of energy levels and observed spectral lines of all ionization stages of Ar was reported in [8]. Many of the papers published on the spectra of two and three times ionized argon (Ar III, Ar IV) are cited in this work [8]. The report by Hansen and Persson [9] that presented a revised and extended analysis of the optical spectrum of Ar III is noteworthy. They used hollow cathode and theta-pinch sources analyzing the 3s²3p⁴, 3s3p⁵, 3p⁶, 3s²3p³4s, 3s²3p³4p, and 3s²3p³3d configurations. Improved energy levels in this ion resulting from the best wavelengths in the literature in the range between 508 Å and 4183 Å were presented by Kaufman and Whaling [10]. For Ar IV, Bredice et al. [11] reanalyzed the 3s²3p³, 3s3p⁴, 3s²3p² (3d + 4s) configurations to obtain new energy levels and classify new transitions. A more recent paper [12] presented an analysis of beam-foil and beam-gas excited spectrum of argon observed in the wavelength region 2965–3090 Å. New transitions in the spectrum of Ar III and Ar IV were also identified.

In the last few decades [13,14,15,16,17,18], there has been intense research on determining and compiling the transition probabilities of ionized argon. In the work of Burger et al. [19], transition probabilities were presented for 38 Ar III and 14 Ar IV spectral lines from the wavelength interval 2400–3080 Å. These were compared to other papers reporting theoretical values [15,17]. In [15], Luna et al. used the Cowan code [20] carried out according to the relativistic Hartree–Fock (HF) approach.

To continue the study of the two and three times ionized argon spectra, a new spectral analysis of these ions is presented in this work. We used our experimental data of the argon spectrum covering the wavelength range 480–6218 Å for the visible ultraviolet (VUV) region. A set of 129 transitions of Ar III and 112 transitions of Ar IV were classified for the first time. Five new energy levels belonging to 3s²3p³4d, 3s²3p³5s odd configurations of Ar III and 10 new energy levels of the 3s²3p²3d and 3s²3p²4p even and odd configurations, respectively, of Ar IV are presented. Theoretical predictions of the configuration structure and transition probabilities for the spectral lines were obtained from the computer code developed by Cowan [20]. The energy matrix was calculated using energy parameters adjusted to fit the experimental energy levels.

2. Experimental Methods

The experimental data for argon were obtained at Centro de Investigaciones Opticas (CIOp). In order to excite the spectra, a capillary-pulsed discharge was used. It consisted of a Pyrex tube about 100 cm long, with an inner diameter of 0.5 cm. The electrodes, placed 80 cm apart, were made of tungsten and covered with indium. Gas excitation was produced by discharging a bank of low-inductance capacitors between 20 and 280 nF and charged up to 20 kV. To study the VUV region, one end of the tube was connected to a vacuum spectrograph and in this way a continuous flow of gas between the gas inlet and the spectrograph was established. Light emitted axially was recorded in the VUV and in the visible regions. In the VUV region, the light was analyzed using a 3 m normal incidence vacuum spectrograph with a concave diffraction grating with 1200 lines/mm and plate factor 2.77 Å/mm in the first diffraction order. To record the spectra, Ilford Q plates were used and known lines of carbon, nitrogen, oxygen, and different noble gas ions served as wavelength standards. The wavelength range above 2000 Å was observed using a diode array detector coupled to a 3.4 m Ebert plane-grating spectrograph with 600 lines/mm and a plate factor of 5 Å/mm in the first diffraction order. Photographic plates were used to record the spectra in the first, second, and third diffraction orders. Thorium lines from an electrodeless discharge were superimposed on the spectrograms and served as reference lines. To distinguish between different states of ionization, the gas pressure, discharge voltage, and number of discharges were varied. Wavelengths above 2000 Å were tabulated in air using the Edlén formula (Sections 1–4 in Reference [20]). The spectrograms were measured with a photoelectric semiautomatic Grant comparator, and the uncertainty in the determination of the wavelength of unperturbed lines was estimated to be ±0.02 Å in the VUV region and ±0.01 Å in the visible region. Energy level values derived from the observed lines were determined by means of an iterative procedure, which took into account the wave numbers of the lines, weighted by their estimated uncertainties. The uncertainty of the adjusted experimental energy level values was assumed to be lower than 2 cm⁻¹.

3. Results and Discussion

In the present work, we used Cowan’s atomic structure package [20], with corrections to the code made by Kramida [21] due to an error in Cowan’s atomic structure theory, to calculate the solution for relativistic Hartree–Fock (HF) equations including configuration interaction for Ar III and Ar IV. We adjusted the values of energy parameters to the experimental energy levels of these ions by means of a least squares calculation. With the adjusted values, we calculated the energy and composition of the levels, as well as the weighted transition probability rate gA [15,20], where g is the statistical weight 2J + 1 of the upper level. We present a revised and extended analysis of 3s²3p³4d, 3s²3p³5s odd configurations for Ar III and of 3s²3p²3d and 3s²3p²4p even and odd configurations for Ar IV. The configuration sets used were 3s²3p⁴, 3s²3p³ (4p,5p,6p), 3s²3p³ (4f,5f), 3s3p⁴3d, 3p⁶, 3s²3p²3d² and 3s3p⁵, 3s²3p³ (3d,4d,5d,6d), 3s²3p³ (4s,5s,6s,7s) for Ar III even and odd parities, respectively, and 3s²3p³, 3s²3p² (4p,5p), 3p⁵, 3s3p³3d, 3s²3p²4f, 3s²3p3d² and 3s3p⁴, 3s²3p² (3d,4d), 3s²3p² (4s,5s), 3s3p²3d², 3p⁴3d for Ar IV odd and even parities, respectively.

Table 1 and Table 2 show the new and calculated energy level values for these ions with the percentage composition in LS notation. We report three new energy levels belonging to 3s²3p³4d and two to 3s²3p³5s configurations of Ar III, and in Ar IV five new energy levels for 3s²3p²3d and five for 3s²3p²4p configurations. The calculated energy level values were obtained by least squares fit [20]. Our calculations included all the energy levels experimentally known.

Table 1. New Ar III energy levels.

Table 2. New Ar IV energy levels.

Table 3 and Table 4 show 23 and 53 new classified lines for Ar III and Ar IV, respectively, that were classified with the new levels presented in this work. We also present 106 and 59 new spectral lines for Ar III and Ar IV, respectively, corresponding to transitions with previously known levels. In these tables we also present gA transition probabilities to compare with the experimental intensity of the new observed lines. In the last columns of these tables we compare the values of gA with those of reference [16]. The observed differences could be due to the fact that weighted values of the energy parameters were used in our work and the calculations presented in reference [16] are ab initio, therefore the composition percentages of the experimental levels are different; besides, the set of configurations used is not exactly the same and there are effects of cancellation factors in our calculations (Sections 14 and 15 in Reference [20]).

Table 3. New classified lines of Ar III.

Table 4. New classified lines of Ar IV.

The least squares calculation results are shown in Table 5, Table 6, Table 7 and Table 8 for Ar III and Ar IV. In Table 5 and Table 6, we show the radial parameters for the even and odd parity configurations of Ar III. In this calculation we also included the illegal-k effective-operator parameters F^k (i,j) and G^k (i,j) (Section 16-7 in Reference [20]). In the case of 3s²3p³3d configuration for the odd parity, we set free the G² (3p, 3d) parameter (there is no HF value for this parameter). The fitted value is in agreement with that published in [10]. In these tables, all the adjusted parameters that were set free are in good agreement with the scaled HF values. The parameter α was left free in the calculation and then fixed to its optimized value. The strong configuration interactions for the even parity (Table 5) between 3s²3p⁴–3s3p⁴3d and 3s²3p⁴–3p⁶ configurations were optimized and fixed at 90%, 85%, and 70% of their HF values, respectively. For the odd parity (Table 6), the interaction integrals between 3s3p⁵–3s²3p³3d and 3s²3p³3d–3s²3p³4d configurations were set free in the calculation. In the energy adjustment of Ar III, the standard deviation was 101 and 339 cm⁻¹ for the even and odd parities, respectively.

Table 5. Energy parameters (cm⁻¹) for the studied even parity configurations of Ar III. HF, Hartree–Fock.

Table 6. Energy parameters (cm⁻¹) for the studied odd parity configurations of Ar III.

Table 7. Energy parameters (cm⁻¹) for the studied odd parity configurations of Ar IV.

Table 8. Energy parameters (cm⁻¹) for the studied even parity configurations of Ar IV.

In Table 7 and Table 8, we show the radial parameters for the odd and even parity configurations of Ar IV. The adjusted parameters in these tables are in accordance with the scaled HF values. The parameter α was left free in the calculation and then fixed to its optimized value, except for the 3s²3p²4s configuration, which was left fixed at the value of zero. The configuration interactions were set to 85% of their HF values. These values are omitted in Table 7 and Table 8. For the even configurations, the integral of interaction between 3s3p⁴ and 3s²3p²3d is significant, as it was seen in reference [11]. The standard deviation was 266 and 242 cm⁻¹ for the odd and even parities, respectively.

It should be mentioned that the accuracy in our calculations of the fitted values of the previously known energy levels are given according to the standard deviation for each of the parities in Ar III and Ar IV.

4. Conclusions

In this work we studied the Ar III and Ar IV spectra covering the wavelength range 480–6218 Å for the visible ultraviolet region using a pulsed electrical discharge. A set of 129 transitions of Ar III and 112 transitions of Ar IV were classified. Five new energy levels belonging to 3s²3p³4d, 3s²3p³5s and 10 new energy levels of 3s²3p²3d, 3s²3p²4p for Ar III and Ar IV, respectively, were presented. Relativistic Hartree–Fock calculations were used. We considered optimized values of the energy parameters using least squares technique where we adjusted the theoretical parameter values to fit the experimental levels.

Author Contributions

Investigation, Writing-Original Draft Preparation, Conceptualization and Atomic calculation, M.R.; Software, R.E.M.C.; Formal Analysis, M.G.; Methodology and Investigation, J.R.A.

Funding

This research received no external funding.

Acknowledgments

This research was supported by the Consejo Nacional de Investigaciones Científicas y Técnicas, Argentina. The Comision de Investigaciones Científicas de la Provıncia de Buenos Aires (CIC), where M. Raineri is a researcher, is also gratefully acknowledged.

Conflicts of Interest

The authors declare no conflict of interest.

References

Ziegler, M.; Rauch, T.; Werner, K.; Kruk, J.W.; Oliveira, C.M. FUV spectroscopy of the central star of planetary nebula Sh 2-216. Astrophys. Space Sci. 2009, 320, 257–260. [Google Scholar] [CrossRef]
Vermal, A.; Lutz, D.; Sturm, E.; Sternberg, A.; Genzel, R.; Vacca, W. A midinfrared spectroscopic survey of starburst galaxies: Excitation and abundances. Astron. Astrophys. 2003, 403, 829–846. [Google Scholar] [CrossRef]
Kunze, D.; Rigopoulou, D.; Lutz, D.; Egami, E.; Feuchtgruber, H.; Genzel, R.; Spoon, H.W.W.; Sturm, E.; Sternberg, A.; Moorwood, A.F.M.; et al. SWS spectroscopy of the colliding galaxies NGC4038/39. Astron. Astrophys. 1996, 315, L101–L104. [Google Scholar]
Celik, M. Spectral measurements of inductivity coupled and helicon discharge modes of a laboratory argon plasma source. Spectrochim. Acta Part B At. Spectrosc. 2011, 66, 149–155. [Google Scholar] [CrossRef]
Lotito, G.; Nelis, T.; Guillot, P.; Günther, D. Characterization of argon metastable species as function of time, space, and current of a pulsed DC glow discharge. Spectrochim. Acta Part B At. Spectrosc. 2011, 66, 619–626. [Google Scholar] [CrossRef]
Ma, Q.L.; Motto-Ros, V.; Lei, W.Q.; Boueri, M.; Bai, X.S.; Zheng, L.J.; Zeng, H.P.; Yu, J. Temporal and spatial dynamics of laser-induced aluminium plasma in argon background at atmospheric pressure: Interplay with the ambient gas. Spectrochim. Acta Part B At. Spectrosc. 2010, 65, 896–907. [Google Scholar] [CrossRef]
Kühn, G.; Könemann, F.; Kock, M. The role of Ar III in quantitative spectroscopy on hot argon plasma. J. Quant. Spectrosc. Radiat. Transf. 2007, 105, 102–110. [Google Scholar] [CrossRef]
Saloman, E.B. Energy Levels and Observed Spectral Lines of Ionized Argon, Ar II through Ar XVIII. J. Phys. Chem. Ref. Data 2010, 39, 033101. [Google Scholar] [CrossRef]
Hansen, J.E.; Persson, W. A revised analysis of the spectrum of Ar III. J. Phys. B 1987, 20, 693–706. [Google Scholar] [CrossRef]
Kaufman, V.; Whaling, W. Improved Wavelengths and Energy Levels of Doubly-Ionized Argon (Ar III). J. Res. Natl. Inst. Stand. Technol. 1996, 101, 691–704. [Google Scholar] [CrossRef] [PubMed]
Bredice, F.; Gallardo, M.; Reyna Almandos, J.G.; Trigueiros, A.G.; Pagan, C.J.B. Revised analysis of triply ionized argon (Ar IV). Phys. Scr. 1995, 51, 446–453. [Google Scholar] [CrossRef]
Nandi, T.; Mishra, A.P.; Jagatap, B.N. Observation of transitions involving core-excited states in Ar III and Ar IV and high-lying singly excited states in Ar I–Ar IV. J. Quant. Spectrosc. Radiat. Transf. 2011, 112, 2771–2778. [Google Scholar] [CrossRef]
Malone, B.S.; Corcoran, W.H. Transition probability measurements in the blue–near–U.V. spectrum of Ar I. J. Quant. Spectrosc. Radiat. Transf. 1966, 6, 443–449. [Google Scholar] [CrossRef]
Whaling, W.; Anderson, W.H.C.; Carle, M.T.; Brault, J.W.; Zarem, H.A. Argon ion line list and level energies in the hollow-cathode discharge. J. Quant. Spectrosc. Radiat. Transf. 1995, 53, 1–22. [Google Scholar] [CrossRef]
Luna, F.R.T.; Bredice, F.; Cavalcanti, G.H.; Trigueiros, A.G. Weighted oscillator strengths and lifetimes for the Ar III spectrum. J. Quant. Spectrosc. Radiat. Transf. 2001, 69, 171–188. [Google Scholar] [CrossRef]
Froese Fischer, C.; Tachiev, G.; Irimia, A. Relativistic energy levels, lifetimes, and transition probabilities for the sodium-like to argon-like sequences. At. Data Nucl. Data Tables 2006, 92, 607–812. [Google Scholar] [CrossRef]
NIST. Atomic Spectra Database Lines (Wavelength Ordered). 2011. Available online: /http://www.physics.nist.govS (accessed on 23 April 2018).
Stancalie, V.; Pais, V.F.; Mihailescu, A. Contributors to the EFDA-TF-ITM. Fine-structure splitting calculation in the Ar III ion: Comparison of perturbative (Breit-Pauli) and non-perturbative (MCDF-EAL) predictions. Eur. Phys. J. D 2012, 66, 84–99. [Google Scholar] [CrossRef]
Burger, M.; Skočić, M.; Gavrilov, M.; Bukvić, S.; Djeniže, S. Experimental transition probabilities in the Ar III and Ar IV UV spectra. J. Quant. Spectrosc. Radiat. Transf. 2012, 113, 1662–1668. [Google Scholar] [CrossRef]
Cowan, R.D. The Theory of Atomic Structure and Spectra; University of California Press: Berkeley, CA, USA, 1981; ISBN 9780520038219. [Google Scholar]
Kramida, A. Configuration interactions of class 11: An error in Cowan’s atomic structure theory. Comput. Phys. Commun. 2017, 215, 47–48. [Google Scholar] [CrossRef]

Table 1. New Ar III energy levels.

Configuration	Term	J	Exp Level (cm⁻¹)	Fitted ^a (cm⁻¹)	Composition ^b
3s²3p³ (²D°) 4d	¹S°	0	267,275.7	267,244	98
3s²3p³ (²P°) 4d	¹F°	3	286,381.9	286,375	78 3s²3p³ (²P°) 4d¹F° + 8 3s²3p³ (²D°) 5d¹F°
3s²3p³ (²P°) 4d	¹P°	1	292,090.9	292,122	63 3s²3p³ (²P°) 4d¹P° + 18 3s²3p³ (²D°) 5d¹P°
3s²3p³ (²D°) 5s	¹D°	2	272,655.2	272,636	57 3s²3p³ (²D°) 5s¹D° + 34 3s²3p³ (²D°) 4d¹D°
3s²3p³ (²P°) 5s	¹P°	1	286,878.2	286,845	97

^a Calculated energy level values obtained using the fitted energy parameters. ^b Percentages below 5% have been omitted.

Table 2. New Ar IV energy levels.

Configuration	Term	J	Exp Level (cm⁻¹)	Fitted ^a (cm⁻¹)	Composition ^b
3s²3p² (¹D) 3d	²F	⁵/₂	185,795.6	185,870	46 3s²3p² (¹D) 3d ²F + 39 3s²3p² (³P) 3d ²F
3s²3p² (¹D) 3d	²F	⁷/₂	186,451.8	186,591	44 3s²3p² (¹D) 3d ²F + 31 3s²3p² (³P) 3d ²F
3s²3p² (¹D) 3d	²P	¹/₂	245,175.2	245,287	57 3s²3p² (¹D) 3d²P + 21 3s²3p² (³P) 3d ²P
3s²3p² (¹S) 3d	²D	⁵/₂	261,761.1	261,946	58 3s²3p² (¹S) 3d ²D + 30 3s²3p² (³P) 3d ²D
3s²3p² (¹S) 3d	²D	³/₂	262,626.1	262,735	55 3s²3p² (¹S) 3d ²D + 31 3s²3p² (³P) 3d ²D
3s²3p² (³P) 4p	²S°	¹/₂	282,726.0	282,596	98
3s²3p² (¹D)4p	²P°	¹/₂	311,018.3	310,973	87 3s²3p² (¹D) 4p²P° + 10 3s²3p² (³P) 4p²P°
3s²3p² (¹D)4p	²P°	³/₂	311,276.3	311,201	76 3s²3p² (¹D) 4p²P° + 123s²3p² (³P) 4p²P°
3s²3p² (¹S)4p	²P°	¹/₂	327,113.4	327,126	96
3s²3p² (¹S)4p	²P°	³/₂	327,388.9	327,333	96

^a Calculated energy level values obtained using the fitted energy parameters. ^b Percentages below 5% have been omitted.

Table 3. New classified lines of Ar III.

Rel. Int.	Observed Wavelength Vac (Å)	Wavenumber (cm⁻¹) σ_obs	Lower Level Conf. Term, J			Upper Level Conf. Term, J			gA (s⁻¹)	gA (s⁻¹) Reference [16]
3	764.09	130,875	3s²3p⁴	¹D	2	3s²3p³ (⁴S°) 3d	⁵D°	1	4.12 × 10⁴	2.20 × 10⁵
4	790.77	126,459	3s3p⁵	³P°	2	3s²3p³ (²P°) 4p	³D	2	1.74 × 10⁷	3.22 × 10⁷
8	797.48	125,395	3s3p⁵	³P°	2	3s²3p³ (²P°) 4p	³S	1	1.77 × 10⁸	4.35 × 10⁸
6	797.75	125,353	3s3p⁵	³P°	1	3s²3p³ (²P°) 4p	³D	1	1.96 × 10⁷	3.64 × 10⁷
7	803.88	124,397	3s3p⁵	³P°	1	3s²3p³ (²P°) 4p	³S	1	1.60 × 10⁸	3.95 × 10⁸
2	807.32	123,867	3s3p⁵	³P°	0	3s²3p³ (²P°) 4p	³S	1	6.66 × 10⁷	3.52 × 10⁷
1	817.90	122,264	3s3p⁵	³P°	2	3s²3p³ (²D°) 4p	¹D	2	1.18 × 10⁶
2	855.01	116,958	3s3p⁵	³P°	1	3s²3p³ (²D°) 4p	³P	0	8.33 × 10⁷	2.18 × 10⁸
6	855.94	116,831	3s3p⁵	³P°	1	3s²3p³ (²D°) 4p	³P	1	3.96 × 10⁷	1.21 × 10⁸
3	887.30	112,702	3s3p⁵	³P°	2	3s²3p³ (²D°) 4p	³F	3	1.25 × 10⁷	9.22 × 10⁶
7	896.02	111,605	3s3p⁵	³P°	2	3s²3p³ (²D°) 4p	³D	3	5.62 × 10⁷	1.78 × 10⁸
3	896.37	111,561	3s3p⁵	³P°	1	3s²3p³ (²D°) 4p	³F	2	2.82 × 10⁶
6	906.18	110,353	3s3p⁵	³P°	1	3s²3p³ (²D°) 4p	³D	2	2.65 × 10⁷	9.18 × 10⁷
2	910.22	109,864	3s3p⁵	³P°	2	3s²3p³ (²D°) 4p	¹P	1	8.82 × 10³
2	1019.59	98,079	3s²3p³ (⁴S°) 3d	³D°	1	3s²3p³ (²P°) 4p	¹S	0	1.13 × 10⁶
6	1048.67	95,359 *	3s²3p³ (⁴S°) 3d	⁵D°	2	3s²3p³ (²D°) 4p	³D	2	1.85 × 10⁵
6	1048.67	95,359 *	3s²3p³ (⁴S°) 3d	⁵D°	3	3s²3p³ (²D°) 4p	³D	2	9.23 × 10³
3	1143.62	87,442	3s²3p³ (⁴S°) 3d	³D°	3	3s²3p³ (²P°) 4p	¹D	2	3.14 × 10⁵
8	1151.15	86,870	3s²3p³ (⁴S°) 3d	⁵D°	1	3s²3p³ (²D°) 4p	³P	0	2.96 × 10⁴
3	1152.92	86,736	3s²3p³ (⁴S°) 3d	⁵D°	2	3s²3p³ (²D°) 4p	³P	1	7.69 × 10⁴
4	1156.63	86,458	3s²3p³ (⁴S°) 3d	⁵D°	1	3s²3p³ (²D°) 4p	³P	2	6.57 × 10⁴
1	1225.27	81,615	3s²3p³ (⁴S°) 3d	⁵D°	2	3s²3p³ (²D°) 4p	³F	3	5.61 × 10⁴
6	1226.52	81,532	3s²3p⁴	¹S	0	3s3p⁵	³P°	1	2.33 × 10⁵
2	1227.88	81,441	3s²3p³ (⁴S°) 4p	⁵P	1	3s²3p³ (²P°) 5s	³P°	2	2.80 × 10⁵
1	1231.13	81,226	3s²3p³ (⁴S°) 4p	⁵P	2	3s²3p³ (²P°) 5s	³P°	1	2.36 × 10³
9	1232.52	81,135	3s3p⁵	¹P°	1	3s²3p³ (²D°) 4p	³D	1	9.26 × 10⁷
1	1246.07	80,252	3s²3p³ (⁴S°) 3d	⁵D°	3	3s²3p³ (²D°) 4p	³D	2	9.23 × 10³
1	1287.22	77,687	3s²3p³ (⁴S°) 4p	³P	1	3s²3p³ (²P°) 5s	¹P°	1	5.26 × 10⁵
4	1294.84	77,232	3s²3p³ (⁴S⁰) 4p	³P	2	3s²3p³ (²P°) 4d	¹F°	3	3.74 × 10⁵
9	1308.25	76,438	3s²3p³ (²D°) 3d	³F°	2	3s²3p³ (²P°) 4p	³S	1	9.63 × 10⁵
2	1382.71	72,322	3s²3p³ (⁴S°) 4p	³P	2	3s²3p³ (²P°) 4d	³F°	3	1.03 × 10⁵
6	1461.38	68,428	3s²3p³ (²D°) 4p	¹P	1	3s²3p³ (²P°) 4d	¹P°	1	1.90 × 10⁸
1	1478.87	67,619	3s²3p³ (⁴S°) 4p	⁵P	1	3s²3p³ (²D°) 5s	³D°	2	3.02 × 10³
1	1479.33	67,598	3s²3p³ (⁴S°) 4p	⁵P	2	3s²3p³ (²D°) 5s	³D°	3	1.19 × 10⁵
1	1498.21	66,746	3s²3p³ (⁴S°) 3d	³D°	2	3s²3p³ (²D°) 4p	¹P	1	1.56 × 10⁷
7	1498.38	66,739	3s²3p³ (⁴S°) 3d	³D°	2	3s²3p³ (²D°) 4p	¹P	1	8.52 × 10⁷
1	1501.77	66,588	3s²3p³ (²P°) 3d	³P°	1	3s²3p³ (²P°) 4p	¹S	0	1.92 × 10³
3	1517.15	65,913	3s²3p³ (⁴S°) 4s	⁵S°	2	3s²3p³ (²P°) 4p	³D	3	4.39 × 10⁶
1	1551.71	64,445	3s²3p³ (⁴S°) 4p	⁵P	1	3s²3p³ (²D°) 4d	³D°	2	2.90 × 10⁵
2	1565.07	63,895	3s²3p³ (⁴S°) 4s	³S°	1	3s²3p³ (²P°) 4p	³P	2	2.47 × 10⁷	3.17 × 10⁷
2	1583.54	63,150	3s²3p³ (²D°) 4p	¹P	1	3s²3p³ (²P°) 5s	¹P°	1	3.88 × 10⁷
1	1584.74	63,102	3s²3p³ (⁴S°) 4p	³P	2	3s²3p³ (²D°) 5s	³D°	3	1.63 × 10⁶
2	1621.91	61,656	3s²3p³ (²D°) 4p	³D	1	3s²3p³ (²P°) 5s	¹P°	1	6.94 × 10⁶
3	1641.85	60,907	3s²3p³ (²D°) 3d	¹S°	0	3s²3p³ (²D°) 4p	¹P	1	1.96 × 10⁸
1	1646.50	60,735	3s²3p³ (²D°) 4p	³D	2	3s²3p³ (²P°) 5s	³P°	1	2.50 × 10⁷
2	1654.12	60,455	3s²3p³ (²D°) 4p	¹P	1	3s²3p³ (²P°) 4d	³D°	1	2.16 × 10⁴
2	1657.39	60,336	3s²3p³ (²D⁰) 4p	³P	0	3s²3p³(²P°) 4d	¹P°	1	7.81 × 10⁵
2	1670.10	59,877	3s²3p³ (²D⁰) 4p	³F	3	3s²3p³ (²P°) 4d	¹F°	3	3.57 × 10⁴
3	1674.09	59,734	3s²3p³ (²D⁰) 4p	³F	4	3s²3p³ (²P°) 4d	¹F°	3	4.57 × 10⁴
1	1756.05	56,946	3s²3p³ (²D°) 4p	³D	1	3s²3p³ (²P°) 4d	³P°	2	3.39 × 10⁶
1	1758.89	56,854	3s²3p³ (²D°) 4p	³D	2	3s²3p³ (²P°) 4d	³P°	1	4.34 × 10³
2	1784.86	56,026	3s²3p³ (²D⁰) 4p	¹D	2	3s²3p³(²P°) 4d	¹P⁰	1	6.97 × 10⁵
1	1818.15	55,001	3s²3p³ (²P°) 3d	³P°	1	3s²3p³ (²P°) 4p	³P	1	3.07 × 10⁷	4.91 × 10⁷
2	1821.26	54,907	3s²3p³ (²P°) 3d	³P°	2	3s²3p³ (²P°) 4p	³P	2	2.59 × 10⁸	3.19 × 10⁸
2	1833.45	54,542	3s²3p³ (²D°) 4p	³P	2	3s²3p³ (²P°) 5s	³P°	1	1.12 × 10⁷
1	1877.34	53,267	3s²3p³ (²D°) 3d	³G°	4	3s²3p³ (²D°) 4p	³D	3	1.39 × 10⁸	3.84 × 10⁷
1	1885.05	53,049	3s²3p³ (²D°) 3d	³G°	3	3s²3p³ (²D°) 4p	³D	2	4.94 × 10⁷	1.79 × 10⁷
3	1925.40	51,939	3s²3p³(²P°) 4p	³D	1	3s²3p³ (²P°) 4d	¹P°	1	1.54 × 10⁷
1	1967.80	50,818	3s²3p³ (²D°) 4p	¹D	2	3s²3p³ (²P°) 5s	¹P⁰	1	3.98 × 10⁷
	Observed Wavelength Air (Å)
6	2041.2	48,991	3s²3p³ (²D⁰) 4p	¹P	1	3s²3p³ (²D°) 5s	¹D°	2	1.67 × 10⁹
1	2339.23	42,736.0	3s²3p³ (²P°) 4p	³P	1	3s²3p³ (²P°) 5s	³P°	1	1.73 × 10⁸
2	2351.80	42,521	3s²3p³ (²P°) 4p	¹D	2	3s²3p³ (²P°) 5s	¹P°	1	1.30 × 10⁹
5	2378.82	42,024.7	3s²3p³ (²P°) 4p	¹D	2	3s²3p³ (²P°) 4d	¹F°	3	5.30 × 10⁹
2	2394.85	41,743.6	3s²3p³ (²P°) 4p	³D	2	3s²3p³ (²P°) 4d	³P°	1	1.46 × 10⁶
4	2572.92	38,854.7	3s²3p³ (²P°) 4p	³P	1	3s²3p³ (²P°) 4d	³P°	1	1.24 × 10⁸
1	2628.26	38,036.6	3s²3p³ (²P°) 4p	³P	2	3s²3p³ (²P°) 4d	³F°	2	5.33 × 10⁶
1	2710.09	36,888.2	3s²3p³ (⁴S°) 4p	³P	2	3s23p³ (⁴S°)4d	⁵D°	3	1.39 × 10⁶
2	2710.36	36,884.5	3s²3p³ (²P°) 4p	¹S	0	3s²3p³ (²P°) 4d	¹P°	1	4.38 × 10⁸
9	2767.39	36,124.5	3s²3p³ (²D°) 4p	¹D	2	3s²3p³ (²D°) 5s	³D°	2	1.42 × 10⁷
3	2771.92	36,065.4	3s²3p³ (²D°) 4p	¹D	2	3s²3p³ (²D°) 5s	³D°	1	1.58 × 10⁶
4	2804.36	35,648.3	3s²3p³ (²D°) 4p	³P	1	3s²3p³ (²D°)4d	¹S°	0	1.51 × 10⁶
4	2891.46	34,574.5	3s²3p³ (²P°) 4s	³P°	2	3s²3p³ (²P°) 4p	¹P	1	2.61 × 10⁷
2	3037.25	32,914.9	3s²3p³ (²D°) 4p	¹D	2	3s²3p³ (²P°) 4d	³D°	1	2.00 × 10⁶
9	3048.47	32,793.8	3s²3p³ (²P°) 3d	³D°	1	3s²3p³ (²P°) 4p	¹D	2	7.18 × 10⁶
1	3075.70	32,503.5 *	3s²3p³ (²P°) 4p	³S	1	3s²3p³ (²D°)4d	³P⁰	0	6.26 × 10⁴
1	3075.70	32,503.5 *	3s²3p³ (²P°) 4p	³D	1	3s²3p³ (²D°) 5s	¹D°	2	6.94 × 10⁵
3	3089.03	32,363.2	3s²3p³ (²P°) 4p	³D	3	3s²3p³ (²D°) 5s	¹D°	2	4.64 × 10³
2	3120.41	32,037.8	3s²3p³ (²P°) 4p	³D	1	3s²3p³ (²D°)5s	³D⁰	2	5.91 × 10⁶
4	3132.13	31,917.9	3s²3p³ (²P°) 4p	³D	1	3s²3p³ (²D°)4d	³S°	1	6.40 × 10⁵
1	3137.82	31,860.0	3s²3p³ (²P°)3d	³D°	1	3s²3p³ (²P°) 4p	³P	2	1.12 × 10⁶	1.04 × 10⁷
6	3140.30	31,834.9	3s²3p³ (²P°) 4p	³D	2	3s²3p³ (²D°) 4d	¹D°	2	1.30 × 10⁷
7	3199.08	31,250.0	3s²3p³ (²P°) 4p	³D	2	3s²3p³ (²D°) 4d	³P°	2	1.04 × 10⁵
6	3245.58	30,802.3	3s²3p³ (²P°) 3d	³D°	2	3s²3p³ (²P°) 4p	¹P	1	4.11 × 10⁷	1.58 × 10⁷
2	3290.37	30,383.0	3s²3p³ (²P°) 4p	¹P	1	3s²3p³ (²D°) 5s	³D°	2	1.33 × 10⁷
8	3300.95	30,285.6	3s²3p³ (²P°) 4p	¹P	1	3s²3p³ (²D°) 4d	¹D°	2	4.58 × 10⁷
8	3352.49	29,820.0	3s²3p³ (²P°) 4p	³S	1	3s²3p³ (²D°) 4d	³D°	2	2.00 × 10⁶
2	3356.47	29,784.7	3s²3p³ (²P°) 4p	³S	1	3s²3p³ (²D°)4d	³D°	1	5.91 × 10⁵
2	3373.35	29,635.6	3s²3p³ (²P°)3d	¹D°	2	3s²3p³ (⁴S°) 4p	³P	2	1.34 × 10²
7	3387.85	29,508.8	3s²3p³ (²P°) 4p	³P	1	3s²3p³ (²D°) 5s	¹D°	2	1.14 × 10⁶
2	3420.12	29,230.4	3s²3p³ (²P°) 4p	³P	2	3s²3p³ (²D°) 5s	¹D°	2	7.43 × 10⁵
4	3442.18	29,043.0	3s²3p³ (²P°) 4p	³P	1	3s²3p³ (²D°) 5s	³D°	2	1.59 × 10⁷
1	3445.79	29,012.6	3s²3p³ (²P°) 4p	¹S	0	3s²3p³ (²P°) 4d	³D°	1	1.81 × 10⁶
3	3449.32	28,982.9	3s²3p³ (²P°) 4p	³P	1	3s²3p³ (²D°) 5s	³D°	1	8.36 × 10⁶
2	3453.61	28,946.9	3s²3p³ (²P°) 4p	³P	1	3s²3p³ (²D°) 4d	¹D°	2	2.18 × 10⁷
5	3456.48	28,922.9	3s²3p³ (²P°) 4p	³P	1	3s²3p³ (²D°) 4d	³S°	1	2.61 × 10⁷
2	3463.81	28,861.7	3s²3p³ (²P°) 4p	³D	1	3s²3p³ (²D°) 4d	³D°	2	5.00 × 10⁶
6	3467.98	28,827.0 *	3s²3p³ (²P°) 4p	³D	1	3s²3p³ (²D°) 4d	³D°	1	1.83 × 10⁷
6	3467.98	28,827.0 *	3s²3p³ (²P°) 4p	³P	2	3s²3p³ (²D°) 5s	³D°	3	4.58 × 10⁷
7	3482.15	28,709.7	3s²3p³ (²P°)4p	³D	3	3s²3p³ (²D°) 4d	³D°	3	5.48 × 10⁷
6	3490.12	28,644.1	3s²3p³ (²P°) 4p	³P	2	3s²3p³ (²D°) 4d	³S°	1	2.71 × 10⁷
2	3501.57	28,550.5	3s²3p³ (²P°) 4p	³P	1	3s²3p³ (²D°) 4d	³P°	0	8.20 × 10⁶
3	3504.54	28,526.3	3s²3p³ (²P°) 4p	³P	1	3s²3p³ (²D°) 4d	³P°	1	7.90 × 10⁵
1	3524.86	28,361.8	3s²3p³ (²P°) 4p	³P	1	3s²3p³ (²D°) 4d	³P°	2	3.55 × 10⁶
7	3532.92	28,297.1	3s²3p³ (²P°) 4p	¹D	2	3s²3p³ (²D°) 5s	¹D°	2	6.12 × 10⁷
6	3546.52	28,188.6	3s²3p³ (²P°) 3d	³D°	2	3s²3p³ (²P°) 4p	³S	1	1.13 × 10⁷
7	3557.68	28,100.2	3s²3p³ (⁴S°) 4p	³P	2	3s²3p³ (²P°) 3d	¹P°	1	1.27 × 10⁴
8	3559.94	28,082.3 *	3s²3p³ (²P°) 4p	³P	2	3s²3p³ (²D°) 4d	³P°	2	6.00 × 10⁶
8	3559.94	28,082.3 *	3s²3p³ (²P°) 4p	³S	1	3s²3p³ (²D°)4d	¹S°	0	6.15 × 10⁵
1	3604.60	27,734.4	3s²3p³ (²P°) 4p	¹D	2	3s²3p³ (²D°) 4d	¹D°	2	1.72 × 10⁷
3	3618.28	27,629.6	3s²3p³ (²P°) 3d	³D°	1	3s²3p³ (²P°) 4p	³S	1	3.69 × 10⁶
8	3632.13	27,524.2	3s²3p³ (²P°)4p	³D	2	3s²3p³ (²D°) 4d	³G°	3	7.87 × 10⁵
2	3674.63	27,205.9	3s²3p³ (²P°)4p	¹P	1	3s²3p³ (²D°) 4d	³D°	2	2.00 × 10⁴
2	3787.06	26,398.2	3s²3p³ (²P°) 4p	¹D	2	3s²3p³ (²D°) 4d	¹P°	1	2.28 × 10⁷
2	3908.78	25,576.2	3s²3p³ (²P°) 4p	³P	2	3s²3p³ (²D°) 4d	³D°	3	1.22 × 10⁶
5	3978.72	25,126.6	3s²3p³ (²P°) 3d	¹D°	2	3s²3p³ (⁴S°) 4p	⁵P	2	4.49 × 10²
3	3989.35	25,059.7	3s²3p³ (²P°) 3d	³D°	2	3s²3p³ (²D°) 4p	¹D	2	2.21 × 10⁶
3	3998.77	25,000.6	3s²3p³ (²P°)4s	¹P°	1	3s²3p³ (²D°) 4p	¹D	2	5.83 × 10⁶	9.23 × 10⁶
4	4012.31	24,916.3	3s²3p³ (²D°) 4p	¹P	1	3s²3p³ (²D°) 4d	³F°	2	5.69 × 10⁴
7	4143.38	24,128.1	3s²3p³ (²P°) 4p	³P	1	3s²3p³ (²D°) 4d	¹S°	0	5.46 × 10⁶
1	4520.87	22,113.4	3s²3p³ (²D°)3d	³P°	2	3s²3p³ (²D°) 4p	¹D	2	1.47 × 10⁶
6	4553.69	21,954.1	3s²3p³ (²D°)3d	³D°	1	3s²3p³ (⁴S°) 4p	³P	1	5.49 × 10⁶	1.68 × 10⁸
7	4693.06	21,302.1	3s²3p³ (²D°)3d	³D°	2	3s²3p³ (⁴S°) 4p	³P	1	1.33 × 10⁷	4.83 × 10⁸
1	5587.80	17,891.2	3s²3p³ (⁴S°)4s	³S°	1	3s²3p³ (⁴S°) 4p	⁵P	1	4.62 × 10⁵
9	5869.96	17,031.2	3s²3p³ (²P°)3d	³D°	3	3s²3p³ (²D°) 4p	¹F	3	1.21 × 10⁶
9	5976.62	16,727.2	3s²3p³ (²P°)3d	¹D°	2	3s²3p³ (²D°) 4p	¹D	2	3.59 × 10⁷
9	6054.43	16,512.3	3s²3p³ (²D°) 4p	¹D	2	3s²3p³ (⁴S°) 5s	³S°	1	4.23 × 10³
7	6167.05	16,210.6	3s²3p³ (²D°) 4p	¹D	2	3s²3p³ (⁴S°) 4d	³D°	1	3.17 × 10⁴
8	6187.84	16,156.3	3s²3p³ (²D°)3d	¹P°	1	3s²3p³ (²D°)4p	¹D	2	1.14 × 10⁷
3	6217.65	15,940.4	3s²3p³ (²D°) 3d	³D°	3	3s²3p³ (⁴S) 4p	⁵P	2	4.48 × 10⁴

* Double classification.

Table 4. New classified lines of Ar IV.

Rel. Int.	Observed Wavelength Vac (Å)	Wavenumber (cm⁻¹) σ_obs	Lower Level Conf. Term, J			Upper Level Conf. Term, J			gA (s⁻¹)	gA (s^-1) Reference [16]
1	480.61	208,068	3s3p⁴	⁴P	¹/₂	3s²3p² (¹S) 4p	²P°	¹/₂	2.30 × 10⁴
4	491.01	203,662	3s²3p³	²D°	³/₂	3s²3p² (³P) 3d	²D	³/₂	5.87 × 10⁹
3	499.48	200,208	3s²3p³	²D°	³/₂	3s²3p² (³P) 3d	⁴P	³/₂	4.41 × 10⁷
2	500.75	199,700	3s²3p³	²D°	³/₂	3s²3p² (³P) 3d	⁴P	⁵/₂	1.97 × 10⁷
5	501.09	199,565	3s²3p³	²D°	⁵/₂	3s²3p² (³P) 3d	⁴P	⁵/₂	1.53 × 10⁸
1	520.90	191,975	3s3p⁴	⁴P	¹/₂	3s²3p² (¹D) 4p	²P°	¹/₂	5.91 × 10³
7	536.08	186,539	3s²3p³	²D°	⁵/₂	3s²3p² (¹D) 3d	²G	⁷/₂	4.11 × 10⁷	2.48 × 10⁷
2	564.06	177,286	3s3p⁴	⁴P	³/₂	3s²3p² (³P) 4p	²P°	¹/₂	5.73 × 10⁵
3	596.65	167,602	3s²3p³	²D°	³/₂	3s²3p² (³P) 3d	⁴D	¹/₂	9.99 × 10⁶	6.18 × 10⁶
2	599.11	166,912	3s3p⁴	⁴P	¹/₂	3s²3p² (³P) 4p	⁴D°	¹/₂	3.00 × 10⁷	1.05 × 10⁷
3	604.76	165,355	3s3p⁴	²D	³/₂	3s²3p² (¹D) 4p	²P°	³/₂	7.34 × 10⁸
2	605.06	165,273	3s3p⁴	²D	⁵/₂	3s²3p² (¹D) 4p	²P°	³/₂	8.37 × 10⁸
2	627.10	159,464	3s²3p³	²D°	⁵/₂	3s²3p² (³P) 3d	⁴F	³/₂	3.00 × 10⁵
6	632.95	157,990	3s3p⁴	²D	⁵/₂	3s²3p² (¹D) 4p	²F°	⁷/₂	3.95 × 10⁸
2	686.52	145,662	3s3p⁴	²D	⁵/₂	3s²3p² (³P) 4p	²D°	⁵/₂	1.43 × 10⁶	6.31 × 10⁷
2	694.89	143,907	3s3p⁴	²D	³/₂	3s²3p² (³P) 4p	⁴P°	⁵/₂	1.05 × 10⁵
2	695.27	143,830	3s²3p² (³P)3d	²P	¹/₂	3s²3p² (¹D) 4p	²P°	³/₂	6.60 × 10⁷
2	698.33	143,199	3s3p⁴	²D	³/₂	3s²3p² (³P) 4p	⁴P°	¹/₂	4.33 × 10⁵
2	716.50	139,567	3s²3p² (³P)3d	⁴D	⁵/₂	3s²3p² (¹S) 4p	²P°	³/₂	1.62 × 10⁴
7	773.31	129,314	3s²3p² (³P)3d	²P	³/₂	3s²3p² (³P) 4p	²P°	¹/₂	2.53 × 10⁸	3.82 × 10⁸
8	779.07	128,358	3s²3p² (³P)3d	²P	¹/₂	3s²3p² (³P) 4p	²P°	³/₂	2.96 × 10⁸	4.56 × 10⁸
1	806.55	123,985	3s²3p² (³P)3d	⁴D	¹/₂	3s²3p² (¹D) 4p	²P°	³/₂	6.66 × 10⁵
7	844.39	118,429	3s²3p² (³P)3d	⁴D	³/₂	3s²3p² (¹D) 4p	²D^o	⁵/₂	2.74 × 10⁶
3	847.68	117,969	3s3p⁴	²S	¹/₂	3s²3p² (³P) 4p	²P°	³/₂	1.78 × 10⁶	1.98 × 10⁷
1	848.39	117,870	3s²3p² (¹D) 3d	²F	⁵/₂	3s²3p² (¹D) 4p	²F°	⁵/₂	1.01 × 10⁹
2	850.80	117,537	3s²3p² (¹D) 3d	²F	⁷/₂	3s²3p² (¹D) 4p	²F°	⁷/₂	1.20 × 10⁹
2	853.14	117,214	3s²3p² (¹D) 3d	²F	⁷/₂	3s²3p² (¹D) 4p	²F°	⁵/₂	1.17 × 10⁸
3	859.34	116,368	3s²3p² (³P) 3d	²P	³/₂	3s²3p² (³P) 4p	²S°	¹/₂	1.04 × 10⁹	1.21 × 10⁹
3	860.82	116,168	3s²3p² (³P) 3d	⁴D	⁵/₂	3s²3p² (¹D) 4p	²F°	⁷/₂	6.59 × 10⁶
3	863.24	115,843	3s²3p² (³P) 3d	⁴D	⁵/₂	3s²3p² (¹D) 4p	²F°	⁵/₂	5.20 × 10⁷
1	903.25	110,711	3s²3p² (³P) 3d	⁴F	⁵/₂	3s²3p² (³P) 4p	⁴S°	³/₂	3.94 × 10⁴
9	922.68	108,380	3s²3p² (³P) 3d	⁴D	¹/₂	3s²3p² (³P) 4p	²P°	¹/₂	3.80 × 10⁶
2	945.05	105,814	3s²3p² (³P) 3d	⁴P	³/₂	3s²3p² (¹S) 4p	²P°	¹/₂	5.74 × 10⁵
1	953.37	104,891	3s3p⁴	²S	¹/₂	3s²3p² (³P) 4p	²S°	¹/₂	2.79 × 10⁶
1	957.32	104,457	3s²3p² (¹D) 3d	²F	⁵/₂	3s²3p² (³P) 4p	²D°	³/₂	3.01 × 10⁹	2.53 × 10⁹
6	958.34	104,347	3s²3p² (³P) 3d	⁴D	³/₂	3s²3p² (³P) 4p	⁴S°	³/₂	2.57 × 10⁷	7.19 × 10⁷
6	959.10	104,264	3s²3p² (³P) 3d	⁴D	³/₂	3s²3p² (³P) 4p	²D°	⁵/₂	9.61 × 10⁶	2.01 × 10⁷
5	962.27	103,921	3s²3p² (³P) 3d	⁴D	⁵/₂	3s²3p² (³P) 4p	⁴S°	³/₂	4.76 × 10⁷	4.93 × 10⁷
2	982.76	101,754	3s²3p² (¹D) 3d	²F	⁵/₂	3s²3p² (³P) 4p	⁴D°	⁷/₂	1.19 × 10⁷	8.94 × 10⁷
7	986.07	101,413	3s²3p² (³P) 3d	⁴D	⁵/₂	3s²3p² (³P) 4p	⁴P°	³/₂	2.15 × 10⁹	2.07 × 10⁹
1	987.70	101,245	3s²3p² (³P) 3d	²D	⁵/₂	3s²3p² (¹S) 4p	²P°	³/₂	1.05 × 10⁹
1	989.12	101,100	3s²3p² (¹D) 3d	²F	⁷/₂	3s²3p² (³P) 4p	⁴D°	⁷/₂	4.13 × 10⁸	3.11 × 10⁸
2	990.57	100,952	3s²3p² (¹D) 3d	²F	⁵/₂	3s²3p² (³P) 4p	⁴D°	⁵/₂	3.03 × 10⁷	2.48 × 10⁸
1	997.06	100,295	3s²3p² (¹D) 3d	²F	⁷/₂	3s²3p² (³P) 4p	⁴D°	⁵/₂	8.36 × 10⁷	4.77 × 10⁷
2	1019.73	98,065	3s²3p² (¹D) 3d	²G	⁷/₂	3s²3p² (¹D) 4p	²D^o	⁵/₂	2.07 × 10⁷
1	1114.60	89,718	3s²3p² (³P) 3d	⁴P	³/₂	3s²3p² (¹D) 4p	²P°	¹/₂	8.89 × 10⁵
4	1118.70	89,390	3s²3p² (³P) 3d	⁴P	¹/₂	3s²3p² (¹D) 4p	²P°	¹/₂	1.26 × 10⁵
1	1127.19	88,716	3s²3p² (¹D) 3d	²D	⁵/₂	3s²3p² (¹S) 4p	²P°	³/₂	7.89 × 10⁷
1	1132.00	88,339	3s²3p² (¹D) 3d	²D	³/₂	3s²3p² (¹S) 4p	²P°	³/₂	8.98 × 10⁶
1	1135.56	88,062	3s3p⁴	²P	³/₂	3s²3p² (¹D) 4p	²P°	¹/₂	2.95 × 10⁷
1	1135.56	88,062	3s²3p² (¹D) 3d	²D	³/₂	3s²3p² (¹S) 4p	²P°	¹/₂	2.34 × 10⁷
1	1146.02	87,259	3s3p⁴	²P	¹/₂	3s²3p² (¹D) 4p	²P°	³/₂	5.06 × 10⁷
2	1217.88	82,115	3s²3p² (¹D) 3d	²P	¹/₂	3s²3p² (¹S) 4p	²P°	³/₂	2.70 × 10⁷
5	1218.52	82,067	3s²3p² (¹D) 3d	²G	⁷/₂	3s²3p² (³P) 4p	⁴P°	⁵/₂	3.34 × 10⁵
6	1232.37	81,145	3s²3p² (³P) 3d	²D	³/₂	3s²3p² (¹D) 4p	²D^o	³/₂	1.23 × 10⁷
5	1233.47	81,072	3s²3p² (³P) 3d	²D	³/₂	3s²3p² (¹D) 4p	²D^o	⁵/₂	1.71 × 10⁷
5	1254.87	79,690	3s²3p² (¹D) 3d	²G	⁹/₂	3s²3p² (³P) 4p	⁴D°	⁷/₂	2.68 × 10⁵
7	1254.97	79,683	3s²3p² (³P) 3d	²D	⁵/₂	3s²3p² (¹D) 4p	²D^o	⁵/₂	4.47 × 10⁷
4	1307.41	76,487	3s²3p² (³P)4s	⁴P	³/₂	3s²3p² (¹S) 4p	²P°	³/₂	1.05 × 10⁵
2	1312.11	76,213	3s²3p² (³P)4s	⁴P	³/₂	3s²3p² (¹S) 4p	²P°	¹/₂	1.00 × 10⁵
1	1333.06	75,015	3s²3p² (³P) 3d	⁴P	⁵/₂	3s²3p² (³P) 4p	²P°	³/₂	4.31 × 10⁶
7	1372.75	72,847	3s3p⁴	²P	³/₂	3s²3p² (³P) 4p	²P°	³/₂	8.47 × 10⁷	3.83 × 10⁷
1	1377.35	72,603	3s²3p² (¹D) 3d	²D	⁵/₂	3s²3p² (¹D) 4p	²P°	³/₂	3.15 × 10⁸
2	1407.94	71,026	3s²3p²(³P) 4s	²P	¹/₂	3s²3p² (¹S) 4p	²P°	¹/₂	2.21 × 10⁷
8	1410.89	70,877	3s²3p² (³P) 3d	⁴P	⁵/₂	3s²3p² (³P) 4p	²D°	⁵/₂	3.09 × 10⁷	3.61 × 10⁷
7	1421.24	70,361	3s²3p² (³P) 3d	⁴P	³/₂	3s²3p² (³P) 4p	²D°	⁵/₂	1.62 × 10⁷	2.10 × 10⁷
1	1433.28	69,770	3s²3p² (³P) 4s	²P	³/₂	3s²3p² (¹S) 4p	²P°	¹/₂	1.26 × 10⁷
4	1439.58	69,465	3s²3p² (³P) 3d	⁴P	⁵/₂	3s²3p² (³P) 4p	²D°	³/₂	1.20 × 10⁷	2.83 × 10⁷
2	1453.74	68,788	3s3p⁴	²P	³/₂	3s²3p² (³P) 4p	⁴S°	³/₂	7.27 × 10⁶	1.88 × 10⁷
7	1487.51	67,226	3s²3p² (¹D) 3d	²D	⁵/₂	3s²3p² (¹D) 4p	²D^o	³/₂	5.18 × 10⁷
5	1489.10	67,155	3s²3p² (¹D) 3d	²D	⁵/₂	3s²3p² (¹D) 4p	²D^o	⁵/₂	1.19 × 10⁹
3	1494.59	66,908	3s²3p² (³P) 3d	²D	³/₂	3s²3p² (³P) 4p	²D°	⁵/₂	2.47 × 10⁷
7	1497.60	66,774	3s²3p² (¹D) 3d	²D	³/₂	3s²3p² (¹D) 4p	²D^o	⁵/₂	1.04 × 10⁸
2	1512.87	66,101	3s²3p² (¹D) 3d	²P	¹/₂	3s²3p² (¹D) 4p	²P°	³/₂	2.96 × 10⁷
2	1538.63	64,993	3s²3p² (¹D) 3d	²D	⁵/₂	3s²3p² (¹D) 4p	²F°	⁵/₂	1.58 × 10⁷
1	1636.69	61,099	3s²3p² (³P) 3d	⁴P	¹/₂	3s²3p² (³P) 4p	²S°	¹/₂	2.48 × 10³	8.40 × 10⁶
1	1646.84	60,722	3s²3p² (¹D) 3d	²P	¹/₂	3s²3p² (¹D) 4p	²D°	³/₂	2.32 × 10⁷
1	1795.85	55,684	3s²3p² (³P) 4s	⁴P	¹/₂	3s²3p² (¹D) 4p	²D^o	³/₂	1.11 × 10⁷
2	1887.01	52,992	3s²3p² (¹D) 3d	²D	⁵/₂	3s²3p² (³P) 4p	²D°	⁵/₂	7.60 × 10⁷	3.22 × 10⁷
1	1953.12	51,200	3s²3p² (¹D) 3d	²D	³/₂	3s²3p² (³P) 4p	²D°	³/₂	4.88 × 10⁷	2.45 × 10⁷
1	1975.10	50,630	3s²3p² (¹D) 3d	²P	¹/₂	3s²3p² (³P) 4p	²P°	³/₂	1.18 × 10⁷	1.29 × 10⁷
2	1980.41	50,495	3s²3p² (¹D) 3d	²P	¹/₂	3s²3p² (³P) 4p	²P°	¹/₂	1.51 × 10⁶	1.83 × 10⁶
	Observed Wavelength Air (Å)
3	2311.05	43,257.1	3s²3p²(¹D) 4s	²D	³/₂	3s²3p² (¹D) 4p	²P°	¹/₂	8.16 × 10⁸
1	2319.82	43,093.6	3s²3p² (³P) 3d	²F	⁷/₂	3s²3p² (³P) 4p	⁴P°	⁵/₂	2.00 × 10⁷
6	2385.63	41,904.1	3s²3p² (¹S) 3d	²D	⁵/₂	3s²3p² (¹D) 4p	²F°	⁵/₂	4.40 × 10⁶
1	2435.91	41,040.0	3s²3p² (¹S) 3d	²D	³/₂	3s²3p² (¹D) 4p	²F°	⁵/₂	3.48 × 10⁷
4	2451.42	40,780.3	3s²3p² (¹D) 3d	²P	¹/₂	3s²3p² (³P) 4p	⁴D°	¹/₂	9.44 × 10³
3	2906.13	34,400.0	3s²3p² (³P) 4s	²P	³/₂	3s²3p² (³P) 4p	⁴S°	³/₂	4.97 × 10⁵
4	2936.85	34,040.1	3s²3p² (¹S) 3d	²D	⁵/₂	3s²3p² (³P) 4p	²P°	³/₂	7.71 × 10⁷	6.40 × 10⁸
3	3013.45	33,174.9	3s²3p² (¹S) 3d	²D	³/₂	3s²3p² (³P) 4p	²P°	³/₂	8.83 × 10⁶	9.85 × 10⁷
8	3025.44	33,043.4	3s²3p² (¹S) 3d	²D	³/₂	3s²3p² (³P) 4p	²P°	¹/₂	3.77 × 10⁷	3.57 × 10⁸
2	3074.86	32,512.4	3s²3p² (³P) 4s	⁴P	¹/₂	3s²3p² (³P) 4p	²S°	¹/₂	3.05 × 10⁶
3	3141.25	31,825.2	3s²3p² (³P) 4s	⁴P	³/₂	3s²3p² (³P) 4p	²S°	¹/₂	5.81 × 10⁶	4.22 × 10⁶
4	3143.89	31,778.3	3s²3p² (³P) 4s	²P	³/₂	3s²3p² (³P) 4p	⁴P°	¹/₂	4.74 × 10⁶
1	3317.29	30,136.4	3s²3p² (³P) 4s	²P	¹/₂	3s²3p² (³P) 4p	⁴D°	³/₂	1.02 × 10⁶
4	3399.88	29,404.4	3s²3p² (³P) 4s	²P	³/₂	3s²3p² (³P) 4p	⁴D°	⁵/₂	1.83 × 10⁶
2	3561.57	28,069.5	3s²3p² (¹S) 3d	²D	⁵/₂	3s²3p² (³P) 4p	⁴P°	⁵/₂	1.33 × 10⁶
4	3618.61	27,627.0	3s²3p² (¹S) 3d	²D	³/₂	3s²3p² (³P) 4p	²D°	³/₂	1.23 × 10⁷	6.96 × 10⁷
1	3639.09	27,471.6	3s²3p² (¹S) 3d	²D	⁵/₂	3s²3p² (³P) 4p	⁴P°	³/₂	1.29 × 10⁵
2	3674.93	27,203.7	3s²3p² (¹S) 3d	²D	³/₂	3s²3p² (³P) 4p	⁴P°	⁵/₂	5.55 × 10⁴
1	3752.79	26,639.2	3s²3p² (³P) 4s	²P	¹/₂	3s²3p² (³P) 4p	²S°	¹/₂	1.07 × 10⁸	6.94 × 10⁷
2	4000.64	24,988.9	3s²3p² (¹S) 3d	²D	⁵/₂	3s²3p² (³P) 4p	⁴D°	⁵/₂	1.73 × 10³
9	4168.14	23,984.8	3s²3p²(¹D) 4s	²D	³/₂	3s²3p² (³P) 4p	⁴S°	³/₂	7.90 × 10²
8	4178.81	23,923.5	3s²3p²(¹D) 4s	²D	⁵/₂	3s²3p² (³P) 4p	²D°	⁵/₂	9.64 × 10⁷	8.11 × 10⁷
6	4182.41	23,902.9	3s²3p²(¹D) 4s	²D	³/₂	3s²3p² (³P) 4p	²D°	⁵/₂	1.01 × 10⁸
6	4044.85	22,511.9	3s²3p²(¹D) 4s	²D	⁵/₂	3s²3p² (³P) 4p	²D°	³/₂	6.02 × 10⁶
3	4285.01	23,330.6	3s²3p² (¹S) 3d	²D	³/₂	3s²3p² (³P) 4p	⁴D°	¹/₂	1.19 × 10⁴
8	4444.96	22,491.1	3s²3p² (¹D) 4s	²D	³/₂	3s²3p² (³P) 4p	²D°	³/₂	4.58 × 10⁷	3.85 × 10⁷
6	4525.46	22,091.0	3s²3p² (¹D) 4s	²D	⁵/₂	3s²3p² (³P) 4p	⁴P°	⁵/₂	3.52 × 10⁶
3	4529.64	22,070.6	3s²3p² (¹D) 4s	²D	³/₂	3s²3p² (³P) 4p	⁴P°	⁵/₂	4.37 × 10⁵
4	4655.59	21,473.5	3s²3p² (¹D) 4s	²D	³/₂	3s²3p² (³P) 4p	⁴P°	³/₂	7.00 × 10⁵
2	4680.08	21,361.2	3s²3p² (¹D) 4s	²D	³/₂	3s²3p² (³P) 4p	⁴P°	½	5.39 × 10³

* Double classification.

Table 5. Energy parameters (cm⁻¹) for the studied even parity configurations of Ar III. HF, Hartree–Fock.

Configuration	Parameter	HF Value	Fitted Value	Fitt/HF ^a
3s²3p⁴	E_av		22,421 ± 52
	F² (3p, 3p)	68,558	57,745 ± 203	0.84
	α		69 (FIX)
	ζ_3p	1005	1096 ± 98	1.09
3s²3p³4p	E_av	219,988	227,971 ± 20	1.04
	F² (3p, 3p)	72,040	56,805 ± 117	0.79
	α		100 (FIX)
	ζ_3p	1114	1659 ± 142	1.49
	ζ_4p	150	143 (FIX)	0.95
	F² (3p, 4p)	14,694	14,240 ± 214	0.97
	G⁰ (3p, 4p)	3979	3343 ± 22	0.84
	G² (3p, 4p)	4556	3441 ± 118	0.75
Configuration Interaction (CI) Integrals
3s²3p⁴–3s3p⁴3d	R¹ (3s3p, 3p3d)	80,053	72,047 (FIX)	0.90
3s²3p⁴–3s3p⁴3d	R¹ (3s3p, 3d 3p)	59,375	50,469 (FIX)	0.85
3s²3p⁴–3p⁶	R¹ (3s3s, 3p3p)	94,238	65,967 (FIX)	0.70

^a Parameters omitted from this table: direct and exchange integrals and spin-orbit ζ parameters set to 85% and 95% of their HF values, respectively; CI integrals were set to 85% of their HF values. The standard deviation for the energy adjustment was 101 cm⁻¹.

Table 6. Energy parameters (cm⁻¹) for the studied odd parity configurations of Ar III.

Configuration	Parameter	HF Value	Fitted Value	Fitt/HF ^a
3s3p⁵	E_av	147,157	150,084 ± 398	1.02
	ζ_3p	1008	1008 ± 399	1.00
	G¹ (3s, 3p)	94,422	77,710 ± 2155	0.82
3s²3p³3d	E_av	173,498	181,366 ± 145	1.04
	F² (3p, 3p)	69,680	54,348 ± 481	0.78
	α		248 (FIX)
	ζ_3p	1046	1176 ± 207	1.12
	ζ_3d	25	24 (FIX)	0.95
	F² (3p, 3d)	54,654	49,263 ± 597	0.90
	G¹ (3p, 3d)	68,216	57,194 ± 626	0.84
	G² (3p, 3d)		5394 ± 463
	G³ (3p, 3d)	40,866	32,109 ± 601	0.78
3s²3p³4s	E_av	189,895	197,135 ± 122	1.04
	F² (3p, 3p)	71,619	54,250 ± 561	0.76
	α		240 (FIX)
	ζ_3p	1104	1049 (FIX)	0.95
	G¹ (3p, 4s)	5735	4923 ± 284	0.86
3s²3p³4d	E_av	261,115	268,449 ± 122	1.03
	F² (3p, 3p)	71,954	57,693 ± 483	0.80
	α		119 (FIX)
	ζ_3p	1109	1949 ± 415	1.76
	ζ_4d	6	6 (FIX)	1.00
	F² (3p, 4d)	11,486	10,068 ± 1375	0.88
	G¹ (3p, 4d)	8905	7143 ± 601	0.80
	G³ (3p, 4d)	5982	5085 (FIX)	0.85
3s²3p³5s	E_av	264,555	272,420 ± 114	1.03
	F² (3p, 3p)	72,136	57,347 ± 631	0.79
	α		86 (FIX)
	ζ_3p	1117	1299 ± 297	1.16
	G¹ (3p, 5s)	1714	1467 ± 299	0.85
Configuration Interaction Integrals
3s3p⁵–3s²3p³3d	R¹ (3p3p, 3s3d)	78,625	61,091 ± 605	0.78
3s²3p³3d–3s²3p³4d	R² (3p3d, 3p4d)	16,765	12,132 ± 1046	0.72
3s²3p³3d–3s²3p³4d	R¹ (3p3d, 4d 3p)	23,116	24,234 ± 1142	1.05
3s²3p³3d–3s²3p³4d	R³ (3p3d, 4d 3p)	14,594	18,936 ± 2310	1.30

^a Parameters omitted from this table: direct and exchange integrals, and spin-orbit ζ parameters set to 85% and 95% of their HFR values, respectively; CI integrals were set to 85% of their HFR values. The standard deviation for the energy adjustment was 339 cm⁻¹.

Table 7. Energy parameters (cm⁻¹) for the studied odd parity configurations of Ar IV.

Configuration	Parameter	HF Value	Fitted Value	Fitt/HF ^a
3s²3p³	E_av		27,428± 135
	F² (3p, 3p)	72,352	66,464 ± 775	0.92
	α		−281 (FIX)
	ζ_3p	1123	1292 ± 253	1.15
3s²3p²4p	E_av	285,513	297,973 ± 64	1.04
	F² (3p, 3p)	75,485	61,386 ± 380	0.81
	α		74 (FIX)
	ζ_3p	1235	1045 ± 194	0.85
	ζ_4p	232	221(FIX)	0.95
	F² (3p, 4p)	19,068	15940 ± 407	0.84
	G⁰ (3p, 4p)	5396	4064 ± 91	0.75
	G² (3p, 4p)	6186	4272 ± 404	0.69

^a Parameters omitted from this table: direct and exchange integrals, and spin-orbit ζ parameters set to 85% and 95% of their HF values, respectively; CI integrals were set to 85% of their HF values. The standard deviation for the energy adjustment was 266 cm⁻¹.