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arXiv · 1705.09813

Time-dependent linear-response variational Monte Carlo

Bastien Mussard·Emanuele Coccia·Roland Assaraf·Matt Otten·C. J. Umrigar·Julien Toulouse
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Abstract

We present the extension of variational Monte Carlo (VMC) to the calculation of electronic excitation energies and oscillator strengths using time-dependent linear-response theory. By exploiting the analogy existing between the linear method for wave-function optimisation and the generalised eigenvalue equation of linear-response theory, we formulate the equations of linear-response VMC (LR-VMC). This LR-VMC approach involves the first-and second-order derivatives of the wave function with respect to the parameters. We perform first tests of the LR-VMC method within the Tamm-Dancoff approximation using single-determinant Jastrow-Slater wave functions with different Slater basis sets on some singlet and triplet excitations of the beryllium atom. Comparison with reference experimental data and with configuration-interaction-singles (CIS) results shows that LR-VMC generally outperforms CIS for excitation energies and is thus a promising approach for calculating electronic excited-state properties of atoms and molecules.

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Bastien Mussard, Emanuele Coccia, Roland Assaraf, Matt Otten, C. J. Umrigar, Julien Toulouse. 2017-05-27. Time-dependent linear-response variational Monte Carlo. https://doi.org/10.1016/bs.aiq.2017.05.005

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