论文标题
采取更准确的绝热连接方法的多差波功能
Toward more accurate adiabatic connection approach for multireference wave functions
论文作者
论文摘要
多形式绝热连接（AC）形式主义是CASSCF和DMRG模型中计算动态相关性的有吸引力的方法。 AC的实际实现是基于两个近似值：i）在零耦合常数限制以及II）固定一单电子和两电子降低的密度矩阵（1和2-RDMS）以及II）扩展随机相位近似（ERPA）。这项工作研究了AC中删除“固定RDM”近似值的效果。对两个电子哈密顿分区进行了分析：小组产品功能和Dyall-Hamiltonians。确切的参考AC积分是由DMRG FCI求解器生成的。研究了两种AC模型，使用精确的1和2-RDMS或其在ERPA方程中耦合常数中的二阶扩展。模型分子的计算表明，提升固定RDM近似是提高现有AC近似准确性的可行方法。
A multiconfigurational adiabatic connection (AC) formalism is an attractive approach to computing dynamic correlation within CASSCF and DMRG models. Practical realizations of AC have been based on two approximations: i) fixing one- and two-electron reduced density matrices (1- and 2-RDMs) at the zero-coupling constant limit and ii) extended random phase approximation (ERPA). This work investigates the the effect of removing the "fixed-RDM" approximation in AC. The analysis is carried out for two electronic Hamiltonian partitionings: the group product function- and the Dyall-Hamiltonians. Exact reference AC integrands are generated from the DMRG FCI solver. Two AC models are investigated, employing either exact 1- and 2-RDMs or their second-order expansions in the coupling constant in the ERPA equations. Calculations for model molecules indicate that lifting the fixed-RDM approximation is a viable way toward improving accuracy of the existing AC approximations.
