<?xml version="1.0" encoding="UTF-8"?><xml><records><record><source-app name="Biblio" version="7.x">Drupal-Biblio</source-app><ref-type>17</ref-type><contributors><authors><author><style face="normal" font="default" size="100%">Gupta, Jitendra</style></author><author><style face="normal" font="default" size="100%">Manohar, Prashant Uday</style></author><author><style face="normal" font="default" size="100%">Ghosh, Aryya</style></author><author><style face="normal" font="default" size="100%">Vaval, Nayana</style></author><author><style face="normal" font="default" size="100%">Pal, Sourav</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Extended coupled cluster through nth perturbation order for molecular response properties: a comparative study</style></title><secondary-title><style face="normal" font="default" size="100%">Chemical Physics</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">Dipole moment</style></keyword><keyword><style  face="normal" font="default" size="100%">Energy functional</style></keyword><keyword><style  face="normal" font="default" size="100%">Extended coupled cluster</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2013</style></year><pub-dates><date><style  face="normal" font="default" size="100%">MAY</style></date></pub-dates></dates><publisher><style face="normal" font="default" size="100%">ELSEVIER SCIENCE BV</style></publisher><pub-location><style face="normal" font="default" size="100%">PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS</style></pub-location><volume><style face="normal" font="default" size="100%">417</style></volume><pages><style face="normal" font="default" size="100%">45-51</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;In this paper, we have presented and analyzed the extended coupled cluster (ECC) energy functional, truncated up to nth perturbation order in which expansion is limit to operators of the single and double excitations. The expression for the first order energy derivatives based on the above truncation schemes has been derived and numerically analyzed. We have done a comparative study for dipole moment in various perturbative ECC (n) methods (2 &amp;lt;= n &amp;lt;= 5) for three systems (HF, H2O and BH) at equilibrium geometry. We have particularly studied two variants of ECC (4) and ECC (5*) method for stretched geometry. We have analyzed the contribution of important terms present in ECC functional based on perturbative argument. We have compared our results with standard coupled cluster (CCSD) as well as cubic truncated ECC and also benchmarked with the full CI results wherever available. (c) 2013 Elsevier B.V. All rights reserved.&lt;/p&gt;</style></abstract><custom3><style face="normal" font="default" size="100%">Foreign</style></custom3><custom4><style face="normal" font="default" size="100%">2.028
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