报告题目 (Title)：Fast Algorithms for FCI Excited States(FCI激发态的快速算法）
报告人 (Speaker)：李颖洲 青年研究员（复旦大学）
报告时间 (Time)：2024年11月27日 (周三) 10:30-11:30
报告地点 (Place)：校本部 GJ303教室
邀请人(Inviter)：涂一辉
报告摘要：An efficient excited state method, named xCDFCI, in the configuration interaction framework, is proposed. xCDFCI extends the unconstrained nonconvex optimization problem in CDFCI to a multicolumn version, for low-lying excited states computation. The optimization problem is addressed via a tailored coordinate descent method. In each iteration, a determinant is selected based on an approximated gradient, and coefficients of all states associated with the selected determinant are updated. A deterministic compression is applied to limit memory usage. We test xCDFCI applied to H2O and N2 molecules under the cc-pVDZ basis set. For both systems, five low-lying excited states in the same symmetry sector are calculated together with the ground state. xCDFCI also produces accurate binding curves of carbon dimer in the cc-pVDZ basis with 10−2 mHa accuracy, where the ground state and four excited states in the same symmetry sector are benchmarked.