A Quantum Monte Carlo Study of Lanthanum

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Figure 1. Time step dependence of the diffusion Monte

Carlo (DMC) energies for La atom.

the DMC energies and the time steps follows a polyno-

mial relationship, this is because the presence of Jastrow

factor that introduces polynomial behavior in the energy

as a function of time step. We performed a polynomial

extrapolation of the energies to zero time step. The ex-

trapolated value at τ = 0 for La is −1.25659 ± 0.000839 H.

For the smallest time step, τ = 0.0001 H−1, we found a

time step error of 0.0019 H and for the largest time step,

τ = 0.01 H−1, a value of −0.0104 H has been found.

In conclusion, the small statistical errors which have

been reported for La and its charged cations in this paper

open the way to the possibility for performing high ac-

curacy QMC calculations for the lanthanides.

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