Abstract
The objective of this chapter is to introduce the reader to fixed-node quantum Monte Carlo methods for atoms and molecules. In the first instance we describe fixed-node diffusion Monte Carlo (FNDMC), followed by a discussion of a more versatile method, Pure-Sampling Quantum Monte Carlo (PSQMC). The former is designed to calculate the ground-state energy, formally without bias save for the fixed-node approximation, by sampling the local energy from a stochastically generated “mixed” electron distribution: ΨΦ0, where Ψ is an input trial function and Φ0 is the unknown, exact ground-state solution to the Schrödinger equation. In addition to the ground-state energy, the latter algorithm also calculates electronic properties, such as the electric moments, again formally without bias within the fixed-node approximation, by sampling estimators for those properties from a stochastically generated “pure-electron distribution,” Φ02. We illustrate pure-sampling with an application to the ground state of ethene. Derivations of expressions that rest at the foundations of FNDMC and PSQMC are given in the last section.
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callSimilar Papers
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
