We present a new form of explicitly correlated wavefunction whose parameters are mainly linear, to circumvent the problem of the optimization of a large number of nonlinear parameters usually encountered with basis sets of explicitly correlated wavefunctions. With this trial wavefunction we have succeeded in minimizing the energy instead of the variance of the local energy, as is more common in quantum Monte Carlo methods. We have applied this wavefunction to the calculation of the energies of Be 3P (1s 22p 2) and Be - 4S o (1s 22p 3) by variational and diffusion Monte Carlo methods. The results compare favourably with those obtained by different types of explicitly correlated trial wavefunction already described in the literature. The energies obtained are improved with respect to the best variational ones found in the literature, and within one standard deviation of the estimated non-relativistic limits.
|Data di pubblicazione:||2001|
|Titolo:||Explicitly correlated trial wavefunctions in quantum Monte Carlo calculations of excited states of Be and Be-|
|Rivista:||JOURNAL OF PHYSICS. B, ATOMIC MOLECULAR AND OPTICAL PHYSICS|
|Digital Object Identifier (DOI):||10.1088/0953-4075/34/3/304|
|Codice identificativo ISI:||WOS:000167121700008|
|Codice identificativo Scopus:||2-s2.0-0035248997|
|Appare nelle tipologie:||Articolo su Rivista|