AUTO_RI

Optimizes the RI basis for non-periodic RI-RS GW calculations. The fitting target combines occupied-empty transitions and exchange products. Atom-local (AA) functions are selected first. Neighbor-pair (AB) functions are also used to fit occupied-empty transitions and exchange products. Currently only non-periodic molecules are supported. [Edit on GitHub]

Keywords

• NEIGHBOR_RADIUS

• OCC_EMPTY_FRONTIER_ORBITAL_WINDOW

• RI_AO_RATIO

Keyword descriptions

NEIGHBOR_RADIUS

Type: real
Default: 3.00000000E+000 [angstrom]
Usage: NEIGHBOR_RADIUS [angstrom] 3.0

Description: The RI basis also contains contractions of Gaussian functions centered on different atoms. An atom pair A-B is included for these contractions when its distance is smaller than NEIGHBOR_RADIUS. Larger radii increase the computational cost. Three angstrom is a reasonable value and usually does not need to be changed. [Edit on GitHub]

OCC_EMPTY_FRONTIER_ORBITAL_WINDOW

Type: real
Default: 5.00000000E+000 [eV]
Usage: OCC_EMPTY_FRONTIER_ORBITAL_WINDOW [eV] 5.0

Description: The exchange contribution to the RI optimization objective includes GW levels within the energy window \([\epsilon_{\mathrm{HOMO}}-w,\epsilon_{\mathrm{LUMO}}+w]\). The default of 5 eV is usually sufficient, for example for GW-BSE excitations up to 10 eV. [Edit on GitHub]

RI_AO_RATIO

Type: real
Default: 2.00000000E+000
Usage: RI_AO_RATIO 2

Description: Ratio between the numbers of optimized RI and AO basis functions. For example, RI_AO_RATIO 3 requires an RI basis with three times as many functions as the AO basis. Compare values such as 1, 1.5, 2, 3 and 4 until the GW energies are converged. Larger values increase time and memory, but also increase the numerical accuracy. [Edit on GitHub]