@conference { ISI:000238284200016, title = {Density functional response approach for electric properties of molecules}, booktitle = {International Conference on Computational Methods in Sciences and Engineering (ICCMSE 2005)}, series = {LECTURE SERIES ON COMPUTER AND COMPUTATIONAL SCIENCES}, volume = {3}, year = {2005}, note = {International Conference on Computational Methods in Sciences and Engineering (ICCMSE 2005), Corinth, GREECE, OCT 21-26, 2005}, month = {OCT}, pages = {142-151}, publisher = {Vsp BV-C/o Brill Acad Publ, Po Box 9000, 2300 Pa Leiden, Netherlands}, organization = {Vsp BV-C/o Brill Acad Publ, Po Box 9000, 2300 Pa Leiden, Netherlands}, address = {Corinth, Greece}, abstract = {

We review in this paper an implementation of the response approach to the Kohn-Sham (KS) density functional theory (DFT) for obtaining the linear and non-linear electric response properties of molecules using Gaussian type orbital basis centered on atoms. We have made a formulation in which the response of the electron density through the solution of the coupled perturbed Kohn-Sham (CPKS) equations has to be obtained only once, instead of iteratively as in the case of completely analytic procedure. Our method is based on a numerical finite-field solution of derivative KS operator, followed by analytic solution of CPKS equation. Further, using the response of the electron density, the dipole moment, polarizability and first-hyperpolarizability of the molecules are evaluated. The method is particularly useful for large systems. We tested our method using HF, BH, H2O and CO as test molecules, for which, high quality ab initio results are available. Further, our study of possible incorporation of non-dynamical electron correlation by studying BH and HF at several internuclear distances is discussed.

}, keywords = {Density functional theory, molecular properties, polarizability, Response approach}, isbn = {90-6764-442-0}, issn = {1573-4196}, author = {Pal, Sourav and Sophy, K. B.}, editor = {Maroulis, G and Simos, T} } @article { ISI:000246282600007, title = {Density functional static dipole polarizability and first-hyperpolarizability calculations of Na-n (n=2, 4, 6, 8) clusters using an approximate CPKS method and its comparison with MP2 calculations}, journal = {Journal of Chemical Theory and Computation}, volume = {3}, number = {3}, year = {2007}, month = {MAY}, pages = {716-727}, publisher = {AMER CHEMICAL SOC}, type = {Article}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

{We report the static dipole polarizability and first-hyperpolarizability of the sodium atom clusters, Na-n

}, issn = {1549-9618}, doi = {10.1021/ct6003627}, author = {Sophy, K. B. and Calaminici, Patrizia and Pal, Sourav} } @article { ISI:000260533000029, title = {Noniterative density functional response approach: application to nonlinear optical properties of p-nitroaniline and its methyl-substituted derivatives}, journal = {Journal of Physical Chemistry A}, volume = {112}, number = {44}, year = {2008}, month = {NOV}, pages = {11266-11272}, publisher = {AMER CHEMICAL SOC}, address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA}, abstract = {

We report the effect of substitution, position of the substituent, and the symmetry on the nonlinear optical properties of p-nitroanline (PNA) and its derivatives using our implementation of the noniterative approximation of couple-perturbed Kohn-Sham (CPKS) equation in the deMon2k. Dipole moment, static polarizability, and first hyperpolarizability of these pi-conjugated donor-acceptor organic derivatives of PNA and its methyl-substituted analogs are calculated using our method at different exchange correlation functionals, namely, BP86, BPW91, and BLYP, using 6-31++G** basis set. A comparison of results obtained by our method with those obtained by MP2 (finite-field perturbation) method is presented in this paper. The effect of optical gap on charge transfer and subsequently on polarizabilities has been illustrated.

}, issn = {1089-5639}, doi = {10.1021/jp806204q}, author = {Sophy, K. B. and Shedge, Sapana V. and Pal, Sourav} }