dftd4_damping_atm Module

Implementation of the Axilrod-Teller-Muto triple dipole dispersion contribution with a modified zero (Chai–Head-Gordon) damping together with the critical radii from the rational (Becke–Johnson) damping.


Uses


Functions

public elemental function triple_scale(ii, jj, kk) result(triple)

Logic exercise to distribute a triple energy to atomwise energies.

Arguments

Type IntentOptional Attributes Name
integer, intent(in) :: ii

Atom indices
integer, intent(in) :: jj

Atom indices
integer, intent(in) :: kk

Atom indices

Return Value real(kind=wp)

Fraction of energy


Subroutines

public subroutine get_atm_dispersion(mol, trans, cutoff, s9, a1, a2, alp, r4r2, c6, dc6dcn, dc6dq, energy, dEdcn, dEdq, gradient, sigma)

Evaluation of the dispersion energy expression

Arguments

Type IntentOptional Attributes Name
class(structure_type), intent(in) :: mol

Molecular structure data
real(kind=wp), intent(in) :: trans(:,:)

Lattice points
real(kind=wp), intent(in) :: cutoff

Real space cutoff
real(kind=wp), intent(in) :: s9

Scaling for dispersion coefficients
real(kind=wp), intent(in) :: a1

Scaling parameter for critical radius
real(kind=wp), intent(in) :: a2

Offset parameter for critical radius
real(kind=wp), intent(in) :: alp

Exponent of zero damping function
real(kind=wp), intent(in) :: r4r2(:)

Expectation values for r4 over r2 operator
real(kind=wp), intent(in) :: c6(:,:)

C6 coefficients for all atom pairs.
real(kind=wp), intent(in), optional :: dc6dcn(:,:)

Derivative of the C6 w.r.t. the coordination number
real(kind=wp), intent(in), optional :: dc6dq(:,:)

Derivative of the C6 w.r.t. the partial charges
real(kind=wp), intent(inout) :: energy(:)

Dispersion energy
real(kind=wp), intent(inout), optional :: dEdcn(:)

Derivative of the energy w.r.t. the coordination number
real(kind=wp), intent(inout), optional :: dEdq(:)

Derivative of the energy w.r.t. the partial charges
real(kind=wp), intent(inout), optional :: gradient(:,:)

Dispersion gradient
real(kind=wp), intent(inout), optional :: sigma(:,:)

Dispersion virial

public subroutine get_atm_dispersion_derivs(mol, trans, cutoff, s9, a1, a2, alp, r4r2, c6, dc6dcn, dc6dq, energy, dEdcn, dEdq, gradient, sigma)

Evaluation of the dispersion energy expression

Arguments

Type IntentOptional Attributes Name
class(structure_type), intent(in) :: mol

Molecular structure data
real(kind=wp), intent(in) :: trans(:,:)

Lattice points
real(kind=wp), intent(in) :: cutoff

Real space cutoff
real(kind=wp), intent(in) :: s9

Scaling for dispersion coefficients
real(kind=wp), intent(in) :: a1

Scaling parameter for critical radius
real(kind=wp), intent(in) :: a2

Offset parameter for critical radius
real(kind=wp), intent(in) :: alp

Exponent of zero damping function
real(kind=wp), intent(in) :: r4r2(:)

Expectation values for r4 over r2 operator
real(kind=wp), intent(in) :: c6(:,:)

C6 coefficients for all atom pairs.
real(kind=wp), intent(in) :: dc6dcn(:,:)

Derivative of the C6 w.r.t. the coordination number
real(kind=wp), intent(in) :: dc6dq(:,:)

Derivative of the C6 w.r.t. the partial charges
real(kind=wp), intent(inout) :: energy(:)

Dispersion energy
real(kind=wp), intent(inout) :: dEdcn(:)

Derivative of the energy w.r.t. the coordination number
real(kind=wp), intent(inout) :: dEdq(:)

Derivative of the energy w.r.t. the partial charges
real(kind=wp), intent(inout) :: gradient(:,:)

Dispersion gradient
real(kind=wp), intent(inout) :: sigma(:,:)

Dispersion virial

public subroutine get_atm_dispersion_energy(mol, trans, cutoff, s9, a1, a2, alp, r4r2, c6, energy)

Evaluation of the dispersion energy expression

Arguments

Type IntentOptional Attributes Name
class(structure_type), intent(in) :: mol

Molecular structure data
real(kind=wp), intent(in) :: trans(:,:)

Lattice points
real(kind=wp), intent(in) :: cutoff

Real space cutoff
real(kind=wp), intent(in) :: s9

Scaling for dispersion coefficients
real(kind=wp), intent(in) :: a1

Scaling parameter for critical radius
real(kind=wp), intent(in) :: a2

Offset parameter for critical radius
real(kind=wp), intent(in) :: alp

Exponent of zero damping function
real(kind=wp), intent(in) :: r4r2(:)

Expectation values for r4 over r2 operator
real(kind=wp), intent(in) :: c6(:,:)

C6 coefficients for all atom pairs.
real(kind=wp), intent(inout) :: energy(:)

Dispersion energy