Multipartitioning many-body perturbation theory calculations on temporary anions: applications to N ₂and CO 

Abstract

The multipartitioning form of the second-order many-body perturbation theory for state-selective effective Hamiltonians is adapted to stabilization calculations of temporary molecular anionic states. We restrict our attention to the simplest case of a system composed of a closed-shell-like molecule and an electron. Pilot applications to the description of the 2 g state of the nitrogen molecular anion and the 2 state of CO − are reported.

Complex absorbing potentials within EOM-CC family of methods: Theory, implementation, and benchmarks

“…We note that a similar scheme has been employed before in the context of stabilization techniques. 69,70 As for the choice of the CAP onset, we employed the square roots of the expectation values α 2 (α = x, y, z) for the ground states calculated at the CCSD level of theory as a starting point and considered the impact of small variations. The values used are r 0…”

“…The scattering of slow electrons by the N 2 molecule has been studied experimentally several times [71][72][73][74][75][76][77][78] so that the 2 g resonance of N − 2 is rather well characterized. Consequently, this resonance has served as a testing ground for numerous theoretical approaches including stabilization techniques, 69,70,79,80 methods based on complex scaling, 10,81,82 CAP-based schemes, 16,26,27,[62][63][64][65][66] as well as other approaches. [83][84][85] Among various aspects, the impact of electron correlation on the resonance position and width 62 as well as their basis-set dependence 26,62,64 have been investigated in detail.…”

Calculation ofS-matrix poles by means of analytic continuation in the coupling constant: Application to the2Πgstate ofHoráček1, Mach2, Urban3 2010Phys. Rev. A310300View full textAdd to dashboardCite

“…[9] Coord. rotation [11] 2 .15 0.27 R matrix [40] 2 .15 0.34 Stabilization [14,15] 2 .62 0.45 Stabilization a [28] 2 .34 0.51 Stabilization b [28] 2 .44 0.32 Stabilization c [29] 2 .38 0.47 Stabilization d [29] 2 .36 0.43 S-matrix pole [31] 2 .24 0.34 Optical potential [32] 2 .43 Complex absorbing potential (CAP) [13] 2 .58 ± 0.13 0.55 ± 0.14 Present CCSD 2.56 ± 0.10 0.55 ± 0.05 this curve of course stays real and at λ = 0 gives a reasonable approximation to the the resonance energy.…”

“…[17,[28][29][30][31][32] to mention only a few). It seems natural therefore to test the performance of the ACCC on this molecule.…”

De-perturbative corrections for charge-stabilized double ionization potential equation-of-motion coupled-cluster method

“…The first one is a spherical potential embedding a molecule (the potential can be represented either approximately, by point charges, or analytically, by an exact spherical potential). [26][27][28][29][30] We will refer to this approach as the charged cage method. In the second approach, the nuclear charge variation (NCV) method, the stabilizing potential is produced by scaling the charge of each nucleus by a certain value.…”