Anderson, Amos G. and Goddard, William A., III (2010) Generalized valence bond wave functions in quantum Monte Carlo. Journal of Chemical Physics, 132 (16). Art. No. 164110. ISSN 0021-9606 http://resolver.caltech.edu/CaltechAUTHORS:20100514-133918748
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We present a technique for using quantum Monte Carlo (QMC) to obtain high quality energy differences. We use generalized valence bond (GVB) wave functions, for an intuitive approach to capturing the important sources of static correlation, without needing to optimize the orbitals with QMC. Using our modifications to Walker branching and Jastrows, we can then reliably use diffusion quantum Monte Carlo to add in all the dynamic correlation. This simple approach is easily accurate to within a few tenths of a kcal/mol for a variety of problems, which we demonstrate for the adiabatic singlet-triplet splitting in methylene, the vertical and adiabatic singlet-triplet splitting in ethylene, 2+2 cycloaddition, and Be_2 bond breaking.
|Additional Information:||© 2010 American Institute of Physics. Received 31 August 2009; accepted 10 March 2010; published online 26 April 2010. We wish to thank the reviewer who pointed out that some error in our CAS wave functions is likely the result of CI coefficient optimization without orbital optimization. We also wish to thank Dan Fisher for his contributions to the software, as well as useful discussions.|
|Subject Keywords:||bonds (chemical), Monte Carlo methods, organic compounds, quantum theory, triplet state, VB calculations, wave functions|
|Classification Code:||PACS: 31.15.xw; 31.15.ae; 02.70.Ss|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||14 May 2010 21:26|
|Last Modified:||26 Dec 2012 12:02|
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