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Improved Estimate of the Dissociation Energy of the Beryllium
Dimer

John Allen White Harkless

Over the years, electronic structure theorists have frequently
returned to the beryllium dimer and its dissociation energy
as a problem of enduring popularity. There are two main
reasons for this popularity. First, the beryllium dimer
is one of the smallest diatoms systems available for study;
in previous years it was one of the few affordable systems
that could be treated with electronic structure. Continuing
improvements in the availability of computing power have
made it possible to apply methods of increasing accuracy
to this system. In addition, description of the beryllium
dimer is challenging for most methods, and almost completely
impossible for simple, so-called "black
box" techniques. Numerous high-accuracy quantum chemistry
techniques have been applied to the dissociation energy
problem; this poster includes the results of a quantum Monte
Carlo (QMC) study of the dimer. In addition to investigating
the success of the QMC method in general for this problem,
we also investigate the effectiveness of different QMC trial
function forms.