INTERACTION_POTENTIAL

References: Guidon2008, Guidon2009

Defines the Coulomb, range-separated, mixed, or truncated interaction operator used for Hartree-Fock exchange. [Edit on GitHub]

Keywords

• CUTOFF_RADIUS

• OMEGA

• POTENTIAL_TYPE

• SCALE_COULOMB

• SCALE_GAUSSIAN

• SCALE_LONGRANGE

• T_C_G_DATA

Keyword descriptions

CUTOFF_RADIUS

Type: real
Default: [angstrom]
Usage: CUTOFF_RADIUS 10.0

Description: Cutoff radius for the truncated \(\frac{1}{r}\) potential or the short-range \(\frac{\mathrm{erfc}(\omega \cdot r)}{r}\) potential. For truncated Coulomb in a periodic cell, choose a radius compatible with the cell dimensions. The default value for short-range potentials when this keyword is omitted is solved from \(\frac{\mathrm{erfc}(\omega \cdot r)}{r} = \epsilon_{\mathrm{schwarz}}\) by Newton-Raphson method, with \(\epsilon_{\mathrm{schwarz}}\) set by SCREENING/EPS_SCHWARZ

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OMEGA

Type: real
Default: 0.00000000E+000
Usage: OMEGA 0.5

Description: Parameter \(\omega\) for short/longrange interaction

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POTENTIAL_TYPE

Type: enum
Default: COULOMB
Usage: POTENTIAL_TYPE SHORTRANGE

Description: Selects the interaction potential used for Hartree-Fock exchange. Periodic hybrid calculations commonly use a short-range, truncated, or mixed potential.

Valid values:

• COULOMB Coulomb potential: \(\frac{1}{r}\)

• SHORTRANGE Shortrange potential: \(\frac{\mathrm{erfc}(\omega \cdot r)}{r}\)

• LONGRANGE Longrange potential: \(\frac{\mathrm{erf}(\omega \cdot r)}{r}\)

• MIX_CL Mix coulomb and longrange potential: \(\frac{1}{r} + \frac{\mathrm{erf}(\omega \cdot r)}{r}\)

• GAUSSIAN Damped Gaussian potential: \(\exp{(-\omega^2 \cdot r^2)}\)

• MIX_LG Mix Gaussian and longrange potential: \(\frac{\mathrm{erf}(\omega \cdot r)}{r} + \exp{(-\omega^2 \cdot r^2)}\)

• IDENTITY Overlap

• TRUNCATED Truncated coulomb potential: if (r < R_c) 1/r else 0

• MIX_CL_TRUNC Truncated Mix coulomb and longrange potential, assumes/requires that the erf has fully decayed at R_c

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SCALE_COULOMB

Type: real
Default: 1.00000000E+000
Usage: SCALE_COULOMB 1.0

Description: Scales Hartree-Fock contribution arising from a coulomb potential. Only valid when doing a mixed potential calculation

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SCALE_GAUSSIAN

Type: real
Default: 1.00000000E+000
Usage: SCALE_GAUSSIAN 1.0

Description: Scales Hartree-Fock contribution arising from a gaussian potential. Only valid when doing a mixed potential calculation

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SCALE_LONGRANGE

Type: real
Default: 1.00000000E+000
Usage: SCALE_LONGRANGE 1.0

Description: Scales Hartree-Fock contribution arising from a longrange potential. Only valid when doing a mixed potential calculation

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T_C_G_DATA

Type: string
Default: t_c_g.dat
Usage: T_C_G_DATA /data/t_c_g.dat

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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