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Article

Vertical Ionization Energies of α-L-Amino Acids as a Function of Their Conformation: an Ab Initio Study

Centre d'Ingéniérie des protéines, Institut de Chimie B6a, Sart Tilman, B4000, Liège, Belgium
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Int. J. Mol. Sci. 2004, 5(11), 301-332; https://doi.org/10.3390/i5110301
Received: 24 September 2004 / Accepted: 9 November 2004 / Published: 30 November 2004
Vertical ionization energies (IE) as a function of the conformation are determined at the quantum chemistry level for eighteen α-L-amino acids. Geometry optimization of the neutrals are performed within the Density Functional Theory (DFT) framework using the hybrid method B3LYP and the 6-31G**(5d) basis set. Few comparisons are made with wave-function-based ab initio correlated methods like MP2, QCISD or CCSD. For each amino acid, several conformations are considered that lie in the range 10-15 kJ/mol by reference to the more stable one. Their IE are calculated using the Outer-Valence-Green's-Functions (OVGF) method at the neutrals' geometry. Few comparisons are made with MP2 and QCISD IE. It turns out that the OVGF results are satisfactory but an uncertainty relative to the most stable conformer at the B3LYP level persists. Moreover, the value of the IE can largely depend on the conformation due to the fact that the ionized molecular orbitals (MO) can change a lot as a function of the nuclear structure. View Full-Text
Keywords: vertical ionization energies; amino acids; ab initio calculations vertical ionization energies; amino acids; ab initio calculations
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MDPI and ACS Style

Dehareng, D.; Dive, G. Vertical Ionization Energies of α-L-Amino Acids as a Function of Their Conformation: an Ab Initio Study. Int. J. Mol. Sci. 2004, 5, 301-332. https://doi.org/10.3390/i5110301

AMA Style

Dehareng D, Dive G. Vertical Ionization Energies of α-L-Amino Acids as a Function of Their Conformation: an Ab Initio Study. International Journal of Molecular Sciences. 2004; 5(11):301-332. https://doi.org/10.3390/i5110301

Chicago/Turabian Style

Dehareng, Dominique, and Georges Dive. 2004. "Vertical Ionization Energies of α-L-Amino Acids as a Function of Their Conformation: an Ab Initio Study" International Journal of Molecular Sciences 5, no. 11: 301-332. https://doi.org/10.3390/i5110301

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