<?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%">Matthew Schmidt</style></author><author><style face="normal" font="default" size="100%">Steve Constable</style></author><author><style face="normal" font="default" size="100%">Christopher Ing</style></author><author><style face="normal" font="default" size="100%">Pierre-Nicholas Roy</style></author></authors></contributors><titles><title><style face="normal" font="default" size="100%">Inclusion of trial functions in the Langevin equation path integral ground state method: Application to parahydrogen clusters and their isotopologues</style></title><secondary-title><style face="normal" font="default" size="100%">Journal of Chemical Physics</style></secondary-title></titles><dates><year><style  face="normal" font="default" size="100%">2014</style></year></dates><volume><style face="normal" font="default" size="100%">140</style></volume><pages><style face="normal" font="default" size="100%">234101</style></pages><language><style face="normal" font="default" size="100%">eng</style></language><abstract><style face="normal" font="default" size="100%">&lt;p&gt;We developed and studied the implementation of trial&amp;nbsp;wavefunctions&amp;nbsp;in the newly proposed&amp;nbsp;Langevin equation&amp;nbsp;Path Integral&amp;nbsp;Ground State&amp;nbsp;(LePIGS) method [S. Constable, M. Schmidt, C. Ing, T. Zeng, and P.-N. Roy,&amp;nbsp;J. Phys. Chem. A&amp;nbsp;&lt;b&gt;117&lt;/b&gt;, 7461 (2013)]. The LePIGS method is based on the Path Integral&amp;nbsp;Ground State(PIGS) formalism combined with Path Integral Molecular Dynamics sampling using a&amp;nbsp;Langevin equation&amp;nbsp;based sampling of the canonical distribution. This LePIGS method originally incorporated a trivial trial&amp;nbsp;wavefunction,&amp;nbsp;ψ&lt;sub&gt;&lt;i&gt;T&lt;/i&gt;&lt;/sub&gt;, equal to unity. The present paper assesses the effectiveness of three different trial&amp;nbsp;wavefunctions&amp;nbsp;on three&amp;nbsp;isotopes&amp;nbsp;of hydrogen for&amp;nbsp;cluster&amp;nbsp;sizes&amp;nbsp;&lt;i&gt;N&lt;/i&gt;&amp;nbsp;= 4, 8, and 13. The trial&amp;nbsp;wavefunctions&amp;nbsp;of interest are the unity trial&amp;nbsp;wavefunction&amp;nbsp;used in the original LePIGS work, a Jastrow trial&amp;nbsp;wavefunction&amp;nbsp;that includes correlations due to hard-core repulsions, and a&amp;nbsp;normal mode&amp;nbsp;trial&amp;nbsp;wavefunction&amp;nbsp;that includes information on the equilibrium geometry. Based on this analysis, we opt for the Jastrow&amp;nbsp;wavefunction&amp;nbsp;to calculate energetic and structural properties for parahydrogen, orthodeuterium, and paratritium&amp;nbsp;clusters&amp;nbsp;of size&amp;nbsp;&lt;i&gt;N&lt;/i&gt;= 4 − 19, 33. Energetic and structural properties are obtained and compared to earlier work based on Monte Carlo PIGS simulations to study the accuracy of the proposed approach. The new results for paratritium&amp;nbsp;clusters&amp;nbsp;will serve as benchmark for future studies. This paper provides a detailed, yet general method for optimizing the necessary parameters required for the study of the&amp;nbsp;ground state&amp;nbsp;of a large variety of systems.&lt;/p&gt;</style></abstract><issue><style face="normal" font="default" size="100%">23</style></issue></record></records></xml>