Semi-stochastic full configuration interaction quantum Monte Carlo: Developments and application

Journal Article · Thu May 14 04:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4920975· OSTI ID:22415763

Kersten, J. A. F. ^[1]; Smart, Simon D. ^[2]; Spencer, J. S. ^[3]; Booth, George H. ^[1]; Alavi, Ali ^[1]

---

1. University Chemical Laboratory, Lensfield Road, Cambridge CB2 1EW (United Kingdom)
2. Max Planck Institute for Solid State Research, Heisenbergstraße 1, 70569 Stuttgart (Germany)
3. Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom)

We expand upon the recent semi-stochastic adaptation to full configuration interaction quantum Monte Carlo (FCIQMC). We present an alternate method for generating the deterministic space without a priori knowledge of the wave function and present stochastic efficiencies for a variety of both molecular and lattice systems. The algorithmic details of an efficient semi-stochastic implementation are presented, with particular consideration given to the effect that the adaptation has on parallel performance in FCIQMC. We further demonstrate the benefit for calculation of reduced density matrices in FCIQMC through replica sampling, where the semi-stochastic adaptation seems to have even larger efficiency gains. We then combine these ideas to produce explicitly correlated corrected FCIQMC energies for the beryllium dimer, for which stochastic errors on the order of wavenumber accuracy are achievable.

• OSTI ID: 22415763
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 18 Vol. 142; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ACCURACY
BERYLLIUM
CONFIGURATION INTERACTION
DENSITY MATRIX
DIMERS
EFFICIENCY
GAIN
MONTE CARLO METHOD
PERFORMANCE
STOCHASTIC PROCESSES
WAVE FUNCTIONS