# STDA

parameters needed and setup for sTDA calculations [Edit on GitHub]

## Keywords

- COULOMB_SR_CUT

- COULOMB_SR_EPS

- DO_EWALD

- DO_EXCHANGE

- EPS_TD_FILTER

- FRACTION

- MATAGA_NISHIMOTO_CEXP

- MATAGA_NISHIMOTO_XEXP

## Keyword descriptions

COULOMB_SR_CUT: real = 2.00000000E+001

  Usage: COULOMB_SR_CUT rcut

  Maximum range of short range part of Coulomb interaction. [Edit on GitHub]

COULOMB_SR_EPS: real = 1.00000000E-003

  Usage: COULOMB_SR_EPS sreps

  Threshold for short range part of Coulomb interaction. [Edit on GitHub]

DO_EWALD: logical = F

  Lone keyword: `T`

  Usage: DO_EWALD

  Use Ewald type method for Coulomb interaction [Edit on GitHub]

DO_EXCHANGE: logical = T

  Lone keyword: `T`

  Usage: DO_EXCHANGE

  Explicitly including or switching off sTDA exchange [Edit on GitHub]

EPS_TD_FILTER: real = 1.00000000E-010

  Usage: EPS_TD_FILTER epsf

  Threshold for filtering the transition density matrix [Edit on GitHub]

FRACTION: real = 0.00000000E+000

  Aliases: HFX_FRACTION

  Usage: FRACTION 0.0

  The fraction of TB Hartree-Fock exchange to use in the Kernel. 0.0 implies no HFX part is used in the kernel. [Edit on GitHub]

MATAGA_NISHIMOTO_CEXP: real = -9.90000000E+001

  Usage: MATAGA_NISHIMOTO_CEXP cexp

  Exponent used in Mataga-Nishimoto formula for Coulomb (alpha). Default value is method dependent! [Edit on GitHub]

MATAGA_NISHIMOTO_XEXP: real = -9.90000000E+001

  Usage: MATAGA_NISHIMOTO_XEXP xexp

  Exponent used in Mataga-Nishimoto formula for Exchange (beta). Default value is method dependent! [Edit on GitHub]