Department of Chemistry, University of Washington, Seattle, Washington 98195-1700, USA.
J Chem Phys. 2009 Nov 28;131(20):204101. doi: 10.1063/1.3266564.
The calculation of doubly excited states is one of the major problems plaguing the modern day excited state workhorse methodology of linear response time dependent Hartree-Fock (TDHF) and density function theory (TDDFT). We have previously shown that the use of a resonantly tuned field within real-time TDHF and TDDFT is able to simultaneously excite both the alpha and beta electrons to achieve the two-electron excited states of minimal basis H(2) and HeH(+) [C. M. Isborn and X. Li, J. Chem. Phys. 129, 204107 (2008)]. We now extend this method to many electron systems with the use of our Car-Parrinello density matrix search (CP-DMS) with a first-principles fictitious mass method for wave function optimization [X. Li, C. L. Moss, W. Liang, and Y. Feng, J. Chem. Phys. 130, 234115 (2009)]. Real-time TDHF/TDDFT is used during the application of the laser field perturbation, driving the electron density toward the doubly excited state. The CP-DMS method then converges the density to the nearest stationary state. We present these stationary state doubly excited state energies and properties at the HF and DFT levels for H(2), HeH(+), lithium hydride, ethylene, and butadiene.
计算双重激发态是困扰现代激发态工作horse 线性响应时间相关 Hartree-Fock（TDHF）和密度泛函理论（TDDFT）的主要问题之一。我们之前已经表明，在实时 TDHF 和 TDDFT 中使用调谐到共振的场能够同时激发 alpha 和 beta 电子，以实现最小基 H（2）和 HeH（+）的双电子激发态[C. M. Isborn 和 X. Li，J. Chem. Phys. 129, 204107（2008）]。现在，我们使用我们的 Car-Parrinello 密度矩阵搜索（CP-DMS）和第一性原理虚构质量方法进行波函数优化[X. Li，C. L. Moss，W. Liang 和 Y. Feng，J. Chem. Phys. 130, 234115（2009）]，将此方法扩展到多电子系统。在激光场扰动的应用过程中使用实时 TDHF/TDDFT，将电子密度推向双重激发态。然后，CP-DMS 方法将密度收敛到最近的稳定态。我们在 HF 和 DFT 水平上为 H（2）、HeH（+）、氢化锂、乙烯和丁二烯呈现这些稳定态双重激发态的能量和性质。
