@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 = {<p>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.</p>},
	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:000304915100006,
	title = {Constrained variational approach for energy derivatives in Intermediate hamiltonian fock-space coupled-cluster theory},
	journal = {Chemical Physics},
	volume = {401},
	year = {2012},
	month = {JUN},
	pages = {45-49},
	publisher = {ELSEVIER SCIENCE BV},
	address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS},
	abstract = {<p>Fock-space multi-reference coupled cluster theory is an efficient method for electronic structure of nearly degenerate cases. However, it suffers from the intruder state problem for large model space. The intermediate Hamiltonian formulation eliminates intruder state problem and helps in the convergence of equations. In this paper we have implemented intermediate Hamiltonian approach in Fock-space coupled cluster method for the response properties. We test our method for the dipole moments of doublet radicals. We report dipole moments of CN, SF and NS radicals. (C) 2011 Elsevier B. V. All rights reserved.</p>},
	keywords = {Constrained variational approach, Fock-space multi-reference coupled cluster, Intermediate Hamiltonian theory, Response approach},
	issn = {0301-0104},
	doi = {10.1016/j.chemphys.2011.10.018},
	author = {Ghosh, Aryya and Gupta, Jitendra and Pal, Sourav and Vaval, Nayana}
}
