Analytically continued Fock space multireference coupled-cluster theory: Application to the Πg2 shape resonance in e-N2 scattering

Abstract

Inclusion of selected higher excitations involving active orbitals in the state-specific multireference coupledcluster theory Analytic evaluation of the nonadiabatic coupling vector between excited states using equation-of-motion coupledcluster theory Fock space multireference coupled cluster calculations based on an underlying bivariational self-consistent field on Auger and shape resonances Resonances in S N 2 reactions: Two-mode quantum calculations for Cl − + CH 3 Br on a coupled-cluster potential energy surfaceThe technique of Fock space multireference coupled-cluster ͑FSMRCC͒ is applied for the first time to the correlated calculation of the energy and width of a shape resonance in an electron-molecule collision. The procedure is based upon combining a complex absorbing potential with FSMRCC theory. Accurate resonance parameters are obtained by solving a small non-Hermitian eigenvalue problem. The potential-energy curve of the 2 ⌸ g state of N 2 − is calculated using the FSMRCC and multireference configuration-interaction ͑MRCI͒ level of theories. Comparison with the single-determinant Hartree-Fock theory indicates that correlation effects are important in determining the behavior of the resonance state.

Electron-atom resonances: The complex-scaled multiconfigurational spin-tensor electron propagator method for the2PBe−shape resonance problem

“…Although we have here presented results for resonance parameter for an atomic system, 2 P Be − , the method can be implemented for investigating shape resonance parameters for molecular systems. We had shown for the 2 Π g N − 2 shape resonance [13] using M 1 , and it is quite consistent with previous literature results [45][46][47][48] and experimental measurements [49,50]. In the molecular case [13], the CS technique for the electron-nuclear Coulomb interaction potential −Z/|r − R| has been implemented so that −(Zη −1 )/|r − Rη −1 |, where Z is a nuclear charge, and r and R are the electronic and nuclear positions relative to an origin of a fixed molecular coordinate system [34].…”

Projected CAP/SAC‐CI method with smooth Voronoi potential for calculating resonance states

“…This requirement naturally limits the electronic structure theories to, for example, configuration interaction type methods and Green's function or equation‐of‐motion type approaches. So far, the CAP method has been incorporated with multireference configuration interaction calculations, Green's function methods, and coupled cluster and a related orbital theories . Recently, the methodologies based on coupled cluster theory of electron‐attachment (EA) framework have been developed; namely, CAP/symmetry‐adapted cluster‐configuration interaction (SAC‐CI) and CAP/equation‐of‐motion coupled cluster .…”

“…So far, the CAP method has been incorporated with multireference configuration interaction calculations, [15][16][17][18][19] Green's function methods, [20,21] and coupled cluster and a related orbital theories. [22,23] Recently, the methodologies based on coupled cluster theory of electron-attachment (EA) framework have been developed; namely, CAP/symmetryadapted cluster-configuration interaction (SAC-CI) [24] and CAP/ equation-of-motion coupled cluster. [25][26][27] The further applications of these methods or related theories have been performed for interesting physical processes; for instance, EA, [28] ionization, and interatomic/intermolecular Coulombic decay.…”

Feed‐control development for succinic acid production with Anaerobiospirillum succiniciproducens

“…CAP method has been successfully used for the study of vibrational quasi bound states,20, 21 i.e., Feshbach resonance. CAP has been successfully used for the study of shape resonance with multireference configuration interaction (MRCI),22–25 Multireference coupled cluster (MRCC),26, 27 Green's function,28–30 Equation of motion coupled cluster (EOM‐CC)31, and the symmetry adapted configuration interaction (SAC‐CI) 32. Position of the resonance state is energy difference of the N electron ground state and the electron attached (N+1) electron state.…”