Mp2PairEnergies

Table of Contents

1. Brief description

Mp2PairEnergies is a matrix \( \epsilon_{ij} \) of dimensions \( N_{\rm o} \times N_{\rm o} \). \( \epsilon_{ij} \) is the electron-pair resolved MP2 correlation energy in the complete basis set limig

\begin{equation} \epsilon_{ij} = \sum_{AB} \frac{ V^{AB}_{ij}(2V^{ij}_{AB}-V^{ji}_{AB}) } { \varepsilon_i + \varepsilon_j - \varepsilon_A - \varepsilon_B }, \end{equation}

where \(A\) and \(B\) refer to a virtual orbitals in a basis set that can be considered complete. \( \epsilon_{ij} \) is used by the BasisSetCorrection algorithm and in the context of the theory CCSD(T*) (Irmler, Gallo, and Grüneis 2021). Mp2PairEnergies needs to be provided by an interfaced electronic structure theory package and can be read in using the Read algorithm.

- name: Read
  in:
    fileName: "Mp2PairEnergies.yaml"
  out:
    tensor: Mp2PairEnergies

2. Specification

An example Mp2PairEnergies.yaml file is given below.

version: 100
type: Tensor
scalarType: Real64
dimensions:
- length:     16
  type: State
- length:     16
  type: State
elements:
  type: TextFile
unit: 0.03674932217563878       # = (Eh/eV)

3. Literature

Irmler, Andreas, Alejandro Gallo, and Andreas Grüneis. 2021. “Focal-Point Approach with Pair-Specific Cusp Correction for Coupled-Cluster Theory.” The Journal of Chemical Physics 154 (June): 234103. doi:10.1063/5.0050054.

Created: 2022-09-19 Mon 15:00