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Cumulant Green's function methods for molecules
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DOI：10.1039/d4fd00037d.png)
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Abstract
En 中文
The cumulant expansion of the Green's function is a computationally efficient beyond-GW approach renowned for its significant enhancement of satellite features in materials. In contrast to the ubiquitous GW approximation of many-body perturbation theory, ab initio cumulant expansions performed on top of GW (GW + C) have demonstrated the capability to handle multi-particle processes by incorporating higher-order correlation effects or vertex corrections, yielding better agreements between experiment and theory for satellite structures. While widely employed in condensed matter physics, very few applications of GW + C have been published on molecular systems. Here, we assess the performance of this scheme on a series of 10-electron molecular systems (Ne, HF, H2O, NH3, and CH4) where full configuration interaction estimates of the outer-valence quasiparticle and satellite energies are available. A detailed derivation of cumulant Green's function methods is presented, and the performance of this scheme in describing outer-valence quasiparticle and satellite energies of molecular systems is explored.
Keywords:
SINGLE-PARTICLE SPECTRUM
DEGENERATE ELECTRON-GAS
INNER-VALENCE IONIZATION
QUANTUM MONTE-CARLO
EXPANSION
SINGULARITIES
EXCITATIONS
SATELLITE
EMISSION
EQUATION