2016/03/08 by Norm M. Tubman, Joonho Lee, Tyler Y. Takeshita +2 · 2 citations
Physics and Astronomy · #cond-mat.str-el #physics.chem-ph #quant-ph
paper · pdf · doi:10.1063/1.4955109
published as J. Chem. Phys. 145, 044112 (2016) · 4 pages, 2 figures
arxiv created 2016/03/08 · arxiv updated 2016/08/23
Development of exponentially scaling methods has seen great progress in tackling larger systems than previously thought possible. One such technique, full configuration interaction quantum Monte Carlo, is a useful algorithm that allows exact diagonalization through stochastically sampling determinants. The method derives its utility from the information in the matrix elements of the Hamiltonian, along with a stochastic projected wave function, to find the important parts of Hilbert space. However, the stochastic representation of the wave function is not required to search Hilbert space efficiently, and here we describe a highly efficient deterministic method to achieve chemical accuracy for a wide range of systems, including the difficult Cr2 dimer. In addition our method also allows efficient calculation of excited state energies, for which we illustrate with benchmark results for the excited states of C2.