Fetherolf Jonathan H, Berkelbach Timothy C
Department of Chemistry, Columbia University, New York, New York 10027, USA.
J Chem Phys. 2021 Feb 21;154(7):074104. doi: 10.1063/5.0035454.
We introduce vibrational heat-bath configuration interaction (VHCI) as an accurate and efficient method for calculating vibrational eigenstates of anharmonic systems. Inspired by its origin in electronic structure theory, VHCI is a selected CI approach that uses a simple criterion to identify important basis states with a pre-sorted list of anharmonic force constants. Screened second-order perturbation theory and simple extrapolation techniques provide significant improvements to variational energy estimates. We benchmark VHCI on four molecules with 12-48 degrees of freedom and use anharmonic potential energy surfaces truncated at fourth and sixth orders. When compared to other methods using the same truncated potentials, VHCI produces vibrational spectra of tens or hundreds of states with sub-wavenumber accuracy at low computational cost.
我们引入振动热浴组态相互作用（VHCI）作为一种精确且高效的方法，用于计算非谐系统的振动本征态。受其在电子结构理论中的起源启发，VHCI是一种经过筛选的组态相互作用方法，它使用一个简单的标准，通过预先排序的非谐力常数列表来识别重要的基态。筛选后的二阶微扰理论和简单的外推技术显著改进了变分能量估计。我们在具有12至48个自由度的四个分子上对VHCI进行基准测试，并使用截断到四阶和六阶的非谐势能面。与使用相同截断势能的其他方法相比，VHCI以低计算成本产生了具有亚波数精度的数十或数百个态的振动光谱。
