Exact two-component equation-of-motion coupled-cluster singles and doubles method using atomic mean-field spin-orbit integrals

2019 ◽  
Vol 150 (7) ◽  
pp. 074102 ◽  
Author(s):  
Ayush Asthana ◽  
Junzi Liu ◽  
Lan Cheng
Keyword(s):  
Mean Field ◽  
Equation Of Motion ◽  
Coupled Cluster ◽  
Spin Orbit ◽  
Two Component

scholarly journals General Framework for Calculating Spin–orbit Couplings Using Spinless One-Particle Density Matrices: Theory and Application to the Equation-of-Motion Coupled-Cluster Wave Functions

2019 ◽  
Author(s):  
Pavel Pokhilko ◽  
Evgeny Epifanovsky ◽  
Anna I. Krylov
Keyword(s):  
Degrees Of Freedom ◽  
Particle Density ◽  
Mean Field ◽  
Transition Density ◽  
Open Shell ◽  
Equation Of Motion ◽  
Wave Functions ◽  
Coupled Cluster ◽  
Spin Orbit ◽  
Matrix Elements

Standard implementations of non-relativistic excited-state calculations compute only one component of spin multiplets (i.e., Ms =0 triplets), however, matrix elements for all components are necessary for calculations of experimentally relevant spin-dependent quantities. To circumvent explicit calculations of all multiplet components, we employ Wigner–Eckart’s theorem. Applied to a reduced one-particle transition density matrix computed for a single multiplet component, Wigner–Eckart’s theorem generates all other spin–orbit matrix elements. In addition to computational efficiency, this approach also resolves the phase issue arising within Born–Oppenheimer’s separation of nuclear and electronic degrees of freedom. A general formalism and its application to the calculations of spin–orbit couplings using equation-of-motion coupled-cluster wave functions is presented. The two-electron contributions are included via the mean-field spin–orbit treatment. Intrinsic issues of constructing spin–orbit mean-field operators for open-shell references are discussed and a resolution is proposed. The method is benchmarked by using several radicals and diradicals. The merits of the approach are illustrated by a calculation of the barrier for spin inversion in a high-spin tris(pyrrolylmethyl)amine Fe(II) complex.

Combining the spin-separated exact two-component relativistic Hamiltonian with the equation-of-motion coupled-cluster method for the treatment of spin–orbit splittings of light and heavy elements

2017 ◽  
Vol 19 (5) ◽  
pp. 3713-3721 ◽  
Author(s):  
Zhanli Cao ◽  
Zhendong Li ◽  
Fan Wang ◽  
Wenjian Liu
Keyword(s):  
Equation Of Motion ◽  
Heavy Elements ◽  
Cluster Method ◽  
Coupled Cluster ◽  
Spin Orbit ◽  
Coupled Cluster Method ◽  
Efficient Treatment ◽  
Two Component

An accurate and efficient treatment of spin–orbit splittings has been achieved by combining the sf-X2C+soc-DKH1 Hamiltonian with the equation-of-motion coupled-cluster method.

scholarly journals General Framework for Calculating Spin–orbit Couplings Using Spinless One-Particle Density Matrices: Theory and Application to the Equation-of-Motion Coupled-Cluster Wave Functions

2019 ◽  
Author(s):  
Pavel Pokhilko ◽  
Evgeny Epifanovsky ◽  
Anna I. Krylov
Keyword(s):  
Degrees Of Freedom ◽  
Particle Density ◽  
Mean Field ◽  
Transition Density ◽  
Open Shell ◽  
Equation Of Motion ◽  
Wave Functions ◽  
Coupled Cluster ◽  
Spin Orbit ◽  
Matrix Elements

Standard implementations of non-relativistic excited-state calculations compute only one component of spin multiplets (i.e., Ms =0 triplets), however, matrix elements for all components are necessary for calculations of experimentally relevant spin-dependent quantities. To circumvent explicit calculations of all multiplet components, we employ Wigner–Eckart’s theorem. Applied to a reduced one-particle transition density matrix computed for a single multiplet component, Wigner–Eckart’s theorem generates all other spin–orbit matrix elements. In addition to computational efficiency, this approach also resolves the phase issue arising within Born–Oppenheimer’s separation of nuclear and electronic degrees of freedom. A general formalism and its application to the calculations of spin–orbit couplings using equation-of-motion coupled-cluster wave functions is presented. The two-electron contributions are included via the mean-field spin–orbit treatment. Intrinsic issues of constructing spin–orbit mean-field operators for open-shell references are discussed and a resolution is proposed. The method is benchmarked by using several radicals and diradicals. The merits of the approach are illustrated by a calculation of the barrier for spin inversion in a high-spin tris(pyrrolylmethyl)amine Fe(II) complex.

Two-component relativistic coupled-cluster methods using mean-field spin-orbit integrals

2018 ◽  
Vol 148 (3) ◽  
pp. 034106 ◽  
Author(s):  
Junzi Liu ◽  
Yue Shen ◽  
Ayush Asthana ◽  
Lan Cheng
Keyword(s):  
Mean Field ◽  
Coupled Cluster ◽  
Spin Orbit ◽  
Coupled Cluster Methods ◽  
Two Component ◽  
Cluster Methods

Spin-orbit effects calculated by two-component coupled-cluster methods: test calculations on AuH, Au2, TlH and Tl2

1998 ◽  
Vol 293 (1-2) ◽  
pp. 97-102 ◽  
Author(s):  
Hyo-Sug Lee ◽  
Young-Kyu Han ◽  
Myeong Cheol Kim ◽  
Cheolbeom Bae ◽  
Yoon Sup Lee
Keyword(s):  
Coupled Cluster ◽  
Spin Orbit ◽  
Coupled Cluster Methods ◽  
Two Component ◽  
Cluster Methods
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