<?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%">Bhattacharya, Debarati</style></author><author><style face="normal" font="default" size="100%">Dutta, Achintya Kumar</style></author><author><style face="normal" font="default" size="100%">Gupta, Jitendra</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%">Perturbative order analysis of the similarity transformed hamiltonian in fock-space coupled cluster theory: difference energy and electric response properties</style></title><secondary-title><style face="normal" font="default" size="100%">Molecular Physics</style></secondary-title></titles><keywords><keyword><style  face="normal" font="default" size="100%">electric response properties</style></keyword><keyword><style  face="normal" font="default" size="100%">Fock space</style></keyword><keyword><style  face="normal" font="default" size="100%">perturbative order</style></keyword><keyword><style  face="normal" font="default" size="100%">similarity transformed Hamiltonian</style></keyword></keywords><dates><year><style  face="normal" font="default" size="100%">2015</style></year><pub-dates><date><style  face="normal" font="default" size="100%">JUL</style></date></pub-dates></dates><number><style face="normal" font="default" size="100%">13-14, SI</style></number><publisher><style face="normal" font="default" size="100%">TAYLOR &amp; FRANCIS LTD</style></publisher><pub-location><style face="normal" font="default" size="100%">4 PARK SQUARE, MILTON PARK, ABINGDON OX14 4RN, OXON, ENGLAND</style></pub-location><volume><style face="normal" font="default" size="100%">113</style></volume><pages><style face="normal" font="default" size="100%">2046-2060</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;A perturbative analysis of the ground-state similarity transformed Hamiltonian and its effect on the various Fock-space coupled cluster (FSCC) sectors is presented through calculation of ionisation potential, electron affinity, excitation energies and response properties. Various truncation schemes of the effective Hamiltonian are presented with explicit form of the defining equations. Based on such a truncation, the approximate methods are labelled as FSCC(n), where n represents the correlation energy of the ionised, electron attached or excited states corrected at least up to nth order within coupled cluster singles and doubles scheme (CCSD). A lower scaling CC2 type of approach (abbreviated as FS-CC2) is compared against the group of FSCC(n) methods for energies. Electric response properties have been compared and contrasted for the two lower scaling methods: FSCC(2) and FS-CC2. The various truncated methods are tested for a number of small molecules. The results obtained from a range of truncated methods are compared against full FSCCSD calculations.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">13-14</style></issue><custom3><style face="normal" font="default" size="100%">&lt;p&gt;Foreign&lt;/p&gt;</style></custom3><custom4><style face="normal" font="default" size="100%">1.837</style></custom4></record></records></xml>