d4_model Derived Type

type, public, extends(dispersion_model) :: d4_model

D4 dispersion model to evaluate C6 coefficients


Components

Type Visibility Attributes Name Initial
real(kind=wp), public, allocatable :: aiw(:,:,:)

Reference dynamic polarizibilities
real(kind=wp), public, allocatable :: c6(:,:,:,:)

Reference C6 coefficients
real(kind=wp), public, allocatable :: cn(:,:)

Reference coordination numbers
real(kind=wp), public, allocatable :: en(:)

Electronegativity
real(kind=wp), public, allocatable :: eta(:)

Chemical hardness
real(kind=wp), public :: ga

Charge scaling height
real(kind=wp), public :: gc

Charge scaling steepness
integer, public :: ncoup

Number of atoms coupled to by pairwise parameters
integer, public, allocatable :: ngw(:,:)

Number of Gaussian weights for each reference
real(kind=wp), public, allocatable :: q(:,:)

Reference partial charges
real(kind=wp), public, allocatable :: r4r2(:)

Expectation values for C8 extrapolation
real(kind=wp), public, allocatable :: rcov(:)

Covalent radii for coordination number
integer, public, allocatable :: ref(:)

Number of reference systems
real(kind=wp), public :: wf

Weighting factor for CN interpolation
real(kind=wp), public, allocatable :: zeff(:)

Effective nuclear charges

Type-Bound Procedures

procedure, public :: get_atomic_c6

Evaluate C6 coefficient

  • private subroutine get_atomic_c6(self, mol, gwvec, gwdcn, gwdq, c6, dc6dcn, dc6dq)

    Calculate atomic dispersion coefficients and their derivatives w.r.t. the coordination numbers and atomic partial charges.

    Arguments

    Type IntentOptional Attributes Name
    class(d4_model), intent(in) :: self

    Instance of the dispersion model
    class(structure_type), intent(in) :: mol

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

    Weighting function for the atomic reference systems
    real(kind=wp), intent(in), optional :: gwdcn(:,:,:)

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

    Derivative of the weighting function w.r.t. the partial charge
    real(kind=wp), intent(out) :: c6(:,:)

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

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

    Derivative of the C6 w.r.t. the partial charge

procedure, public :: get_polarizibilities

Evaluate atomic polarizibilities

  • private subroutine get_polarizibilities(self, mol, gwvec, gwdcn, gwdq, alpha, dadcn, dadq)

    Calculate atomic polarizibilities and their derivatives w.r.t. the coordination numbers and atomic partial charges.

    Arguments

    Type IntentOptional Attributes Name
    class(d4_model), intent(in) :: self

    Instance of the dispersion model
    class(structure_type), intent(in) :: mol

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

    Weighting function for the atomic reference systems
    real(kind=wp), intent(in), optional :: gwdcn(:,:,:)

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

    Derivative of the weighting function w.r.t. the partial charge
    real(kind=wp), intent(out) :: alpha(:)

    Static polarizibilities for all atoms.
    real(kind=wp), intent(out), optional :: dadcn(:)

    Derivative of the polarizibility w.r.t. the coordination number
    real(kind=wp), intent(out), optional :: dadq(:)

    Derivative of the polarizibility w.r.t. the partial charge

procedure, public :: weight_references

Generate weights for all reference systems

  • private subroutine weight_references(self, mol, cn, q, gwvec, gwdcn, gwdq)

    Calculate the weights of the reference system and the derivatives w.r.t. coordination number for later use.

    Arguments

    Type IntentOptional Attributes Name
    class(d4_model), intent(in) :: self

    Instance of the dispersion model
    class(structure_type), intent(in) :: mol

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

    Coordination number of every atom
    real(kind=wp), intent(in) :: q(:)

    Partial charge of every atom
    real(kind=wp), intent(out) :: gwvec(:,:,:)

    weighting for the atomic reference systems
    real(kind=wp), intent(out), optional :: gwdcn(:,:,:)

    derivative of the weighting function w.r.t. the coordination number
    real(kind=wp), intent(out), optional :: gwdq(:,:,:)

    derivative of the weighting function w.r.t. the charge scaling

Source Code

   type, extends(dispersion_model) :: d4_model

      !> Weighting factor for CN interpolation
      real(wp) :: wf

   contains

      !> Generate weights for all reference systems
      procedure :: weight_references

      !> Evaluate C6 coefficient
      procedure :: get_atomic_c6

      !> Evaluate atomic polarizibilities
      procedure :: get_polarizibilities

   end type d4_model