EXACT_EXCHANGE

Whether exact-exchange should be added to the kernel and if so, with which fraction and operator. [Edit on GitHub]

Subsections

RI_METRIC

Keywords

SECTION_PARAMETERS
CUTOFF_RADIUS
EPS_RANGE
EPS_SCREENING
OMEGA
POTENTIAL_TYPE
SCALE
T_C_G_DATA

Keyword descriptions

SECTION_PARAMETERS

Type: logical
Default: F
Lone keyword: T
Usage: &EXACT_EXCHANGE {logical}

Description: Enables the addition of exact exchange to the kernel.

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CUTOFF_RADIUS

Type: real
Default: 0.00000000E+000
Aliases: R_C, RC, RANGE
Usage: CUTOFF_RADIUS {double}

Description: The cutoff radius (in Angstrom) for the truncated Coulomb operator.

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EPS_RANGE

Type: real
Default: 1.00000000E-006
Usage: EPS_RANGE = {double}

Description: The threshold to determine the effective range of the short range operator: erfc(omega*eff_range)/eff_range = EPS_RANGE

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EPS_SCREENING

Type: real
Default: 1.00000000E-008
Aliases: EPS_SCREEN

Description: A threshold to determine which primitive 3-center integrals are kept for contraction, as the latter operation can be expensive (especially for large basis sets ). If |(ab|c)| < EPS_SCREENING, it is discarded.

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OMEGA

Type: real
Default: 0.00000000E+000
Usage: OMEGA {double}

Description: The range parameter for the short range operator (in 1/a0).

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POTENTIAL_TYPE

Type: enum
Default: COULOMB
Aliases: OP, OPERATOR, POTENTIAL
Usage: OPERATOR {string}

Description: The type of operator used for exact exchange. The standard Coulomb operator cannot be used in periodic systems.

Valid values:

COULOMB Standard Coulomb operator: 1/r
TRUNCATED Truncated Coulomb operator: 1/r if r < R_c, 0 otherwise
SHORTRANGE Short range: erfc(omega*r)/r

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SCALE

Type: real
Default: 1.00000000E+000
Aliases: FRACTION

Description: Scaling of the exact exchange contribution.

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T_C_G_DATA

Type: string
Default: t_c_g.dat
Usage: T_C_G_DATA {string}

Description: Location of the file t_c_g.dat that contains the data for the evaluation of the truncated gamma function

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