dftd4_damping_rational Module

Implementation of the rational (Becke–Johnson) damping function.


Uses


Derived Types

type, public, extends(damping_param) ::  rational_damping_param

Rational (Becke-Johnson) damping model

Components

Type Visibility Attributes Name Initial
real(kind=wp), public :: a1
real(kind=wp), public :: a2
real(kind=wp), public :: alp = 16.0_wp
real(kind=wp), public :: s6 = 1.0_wp
real(kind=wp), public :: s8
real(kind=wp), public :: s9 = 1.0_wp

Type-Bound Procedures

procedure, public :: get_dispersion2 ../../

Evaluate pairwise dispersion energy expression
procedure, public :: get_dispersion3 ../../

Evaluate ATM three-body dispersion energy expression
procedure, public :: get_pairwise_dispersion2 ../../

Evaluate pairwise representation of additive dispersion energy
procedure, public :: get_pairwise_dispersion3 ../../

Evaluate pairwise representation of non-additive dispersion energy

Functions

private 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

private subroutine get_dispersion2(self, mol, trans, cutoff, r4r2, c6, dc6dcn, dc6dq, energy, dEdcn, dEdq, gradient, sigma)

Evaluation of the dispersion energy expression

Arguments

Type IntentOptional Attributes Name
class(rational_damping_param), intent(in) :: self

Damping parameters
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) :: 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

private subroutine get_dispersion3(self, mol, trans, cutoff, r4r2, c6, dc6dcn, dc6dq, energy, dEdcn, dEdq, gradient, sigma)

Evaluation of the dispersion energy expression

Arguments

Type IntentOptional Attributes Name
class(rational_damping_param), intent(in) :: self

Damping parameters
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) :: 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

private subroutine get_dispersion_derivs(self, mol, trans, cutoff, r4r2, c6, dc6dcn, dc6dq, energy, dEdcn, dEdq, gradient, sigma)

Evaluation of the dispersion energy expression

Arguments

Type IntentOptional Attributes Name
class(rational_damping_param), intent(in) :: self

Damping parameters
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) :: 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

private subroutine get_dispersion_energy(self, mol, trans, cutoff, r4r2, c6, energy)

Evaluation of the dispersion energy expression

Arguments

Type IntentOptional Attributes Name
class(rational_damping_param), intent(in) :: self

Damping parameters
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) :: 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

private subroutine get_pairwise_dispersion2(self, mol, trans, cutoff, r4r2, c6, energy)

Evaluation of the dispersion energy expression projected on atomic pairs

Arguments

Type IntentOptional Attributes Name
class(rational_damping_param), intent(in) :: self

Damping parameters
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) :: 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

private subroutine get_pairwise_dispersion3(self, mol, trans, cutoff, r4r2, c6, energy)

Evaluation of the dispersion energy expression

Arguments

Type IntentOptional Attributes Name
class(rational_damping_param), intent(in) :: self

Damping parameters
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) :: 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