Search for Articles:
Title / Keyword
Author / Affiliation / Email
Journal
Article Type
 
 
Advanced Search
 
Section
Special Issue
Volume
Issue
Number
Page
 

Saved Queries

Sign in to use this feature.

Search Filter Reset All

Years

Between: -

Subjects

remove_circle_outline
remove_circle_outline
remove_circle_outline
Add Subjects Reset
Select Subjects

Journals

remove_circle_outline
Add Journals Reset
Select Journals

Article Types

remove_circle_outline
Add Article Types Reset
Select Article Types

Countries / Regions

remove_circle_outline
remove_circle_outline
Add Countries / Regions Reset
Select Countries / Regions
Update Search
share announcement

Search Results (3)

Search Parameters:
Authors = Humberto J. Soscún Machado

Order results
Result details
Results per page
Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
15 pages, 227 KiB  
Article
Density Functional Studies of the Dipole Polarizabilities of Substituted Stilbene, Azoarene and Related Push-Pull Molecules
by Alan Hinchliffe, Beatrice Nikolaidi and Humberto J. Soscún Machado
Int. J. Mol. Sci. 2004, 5(8), 224-238; https://doi.org/10.3390/i5050224 - 30 Sep 2004
Cited by 36 | Viewed by 11087
Abstract
We report high quality B3LYP Ab Initio studies of the electric dipole polarizability of three related series of molecules: para-XC6H4Y, XC6H4CH=CHC6H4Y and XC6H4N=NC6H4Y, where X and Y represent H together with the six various activating through deactivating groups NH2, OH, OCH3, CHO, CN [...] Read more.
We report high quality B3LYP Ab Initio studies of the electric dipole polarizability of three related series of molecules: para-XC6H4Y, XC6H4CH=CHC6H4Y and XC6H4N=NC6H4Y, where X and Y represent H together with the six various activating through deactivating groups NH2, OH, OCH3, CHO, CN and NO2. Molecules for which X is activating and Y deactivating all show an enhancement to the mean polarizability compared to the unsubstituted molecule, in accord with the order given above. A number of representative Ab Initio calculations at different levels of theory are discussed for azoarene; all subsequent Ab Initio polarizability calculations were done at the B3LYP/6-311G(2d,1p)//B3LYP/6-311++G(2d,1p) level of theory. We also consider semi-empirical polarizability and molecular volume calculations at the AM1 level of theory together with QSAR-quality empirical polarizability calculations using Miller’s scheme. Least-squares correlations between the various sets of results show that these less costly procedures are reliable predictors of for the first series of molecules, but less reliable for the larger molecules. Full article
►▼ Show Figures

Figure 1

10 pages, 50 KiB  
Article
Density Functional Studies of Molecular Polarizabilities. 10. Fulvenes and Fulvalenes
by Alan Hinchliffe and Humberto J. Soscún Machado
Int. J. Mol. Sci. 2000, 1(3), 39-48; https://doi.org/10.3390/ijms1030039 - 4 Sep 2000
Cited by 19 | Viewed by 10456
Abstract
We report accurate Ab Initio Hartree Fock (HF) and Density Functional Theory (DFT) studies of the static dipole polarizabilities and first hyperpolarizabilities of the [n] fulvene and the [n,m] fulvalene series of molecules (with n, m = 3,5,7). Calculations are also reported for [...] Read more.
We report accurate Ab Initio Hartree Fock (HF) and Density Functional Theory (DFT) studies of the static dipole polarizabilities and first hyperpolarizabilities of the [n] fulvene and the [n,m] fulvalene series of molecules (with n, m = 3,5,7). Calculations are also reported for the parent cycloalkenes: cyclopropene, cyclopentadiene and cycloheptatriene (1-3 respectively). Geometries were optimized at the HF/6-311G(3d,2p) level of theory. All the fulvenes (4-6) and the smaller fulvalenes (7, 9 and 10) are found to be planar. Pentaheptafulvalene (11) is slightly non-planar whilst heptafulvalene (12) has a folded C2h structure. Calculated C-C bond lengths are consistently smaller than the experimental values. Dipole polarizabilities and non-zero hyperpolarizabilities were calculated at the HF/6-311++G(3d,2p) and BLYP/6-311++G(3d,2p) levels of theory, using HF/6-311G(3d,2p) geometries. Dipole polarizabilities correlate well with those given on the basis of atom additivity. Molecules (8), (9) and (11) show very large dipole hyperpolarizabilities. Full article
►▼ Show Figures

Figure 1

9 pages, 37 KiB  
Article
Density Functional Studies of Molecular Polarizabilities. 7. Anthracene and Phenanthrene
by Alan Hinchliffe and Humberto J. Soscun Machado
Int. J. Mol. Sci. 2000, 1(1), 8-16; https://doi.org/10.3390/ijms1010008 - 28 Mar 2000
Cited by 28 | Viewed by 12051
Abstract
We report accurate Ab Initio studies of the static dipole polarizabilities of anthracene and phenanthrene. Geometries were optimized at the HF/6-311G(3d,2p) level of theory. Dipole polarizabilities were calculated at the HF/6-311++G(3d,2p) and BLYP/6-311++G(3d,2p) levels of theory, using HF/6-311G(3d,2p) geometries. The calculated dipole polarizabilities [...] Read more.
We report accurate Ab Initio studies of the static dipole polarizabilities of anthracene and phenanthrene. Geometries were optimized at the HF/6-311G(3d,2p) level of theory. Dipole polarizabilities were calculated at the HF/6-311++G(3d,2p) and BLYP/6-311++G(3d,2p) levels of theory, using HF/6-311G(3d,2p) geometries. The calculated dipole polarizabilities for anthracene are compared with experiment. Inclusion of electron correlation using the BLYP procedure increases the L and M components of the dipole polarizability, but not the perpendicular (N) component. Examination of corresponding BLYP results for the polyacene series benzene, naphthalene and anthracene shows that the normal component of the dipole polarizability scales linearly with the number of benzene ring units, with an increment of 20.8 au. The medium component also scales linearly with an increment of 42.8 atomic units. The long component does not scale linearly. Semi-emiprical AM1 calculations are also given for comparison; the normal component of the dipole polarizability tensor is poorly represented by such calculations. Full article
►▼ Show Figures

Figure 1

Show export options expand_more Show export options expand_less
Select all
Export citation of selected articles as:
 
Displaying article 1-50 on page 1 of 1.
Back to TopTop