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Optimization of trial wave functions for use in quantum Monte Carlo with application to LiH

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Show simple item record Chʻen, Hung-tʻao. en_US 2009-07-09T18:39:19Z 2009-07-09T18:39:19Z 1988-07-09T18:39:19Z
dc.description.abstract Methods for both partial and full optimization of wavefunction parameters are explored, and these are applied to the LiH molecule. A partial optimization can be easily performed with little difficulty. But to perform a full optimization we must avoid a wrong minimum, and deal with linear-dependency, time step-dependency and ensemble-dependency problems. Five basis sets are examined. The optimized wavefunction with a 3-function set gives a variational energy of -7.998 + 0.005 a.u., which is comparable to that (-7.990 + 0.003) 1 of Reynold's unoptimized \fin ( a double-~ set of eight functions). The optimized wavefunction with a double~ plus 3dz2 set gives ari energy of -8.052 + 0.003 a.u., which is comparable with the fixed-node energy (-8.059 + 0.004)1 of the \fin. The optimized double-~ function itself gives an energy of -8.049 + 0.002 a.u. Each number above was obtained on a Bourrghs 7900 mainframe computer with 14 -15 hrs CPU time. en_US
dc.language.iso eng en_US
dc.publisher Brock University en_US
dc.subject Lithium hydride. en_US
dc.subject Mathematical optimization. en_US
dc.subject Wave functions. en_US
dc.subject Monte Carlo method. en_US
dc.subject Quantum chemistry. en_US
dc.title Optimization of trial wave functions for use in quantum Monte Carlo with application to LiH en_US
dc.type Electronic Thesis or Dissertation en_US M.Sc. Chemistry en_US Masters en_US
dc.contributor.department Department of Chemistry en_US Faculty of Mathematics and Science en_US

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