mbd_calc_t – libMBD

type, public :: mbd_calc_t

Represents an MBD calculation.

Type-Bound Procedures

init destroy switch_forces update_coords update_lattice_vectors update_vdw_params_custom update_vdw_params_from_ratios update_vdw_params_nl evaluate_vdw_method get_gradients get_vdw_params_ratios_gradients get_lattice_derivs get_lattice_stress get_spectrum_modes get_rpa_orders get_exception

Type-Bound Procedures

procedure, public :: init => mbd_calc_init

private subroutine mbd_calc_init(this, input)

Initialize an MBD calculation from an MBD input.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(inout),		target	::	this
type(mbd_input_t),	intent(in)			::	input	MBD input.

procedure, public :: destroy => mbd_calc_destroy

private subroutine mbd_calc_destroy(this)

Finalize an MBD calculation.

Arguments

Type Intent Optional Attributes Name

class(mbd_calc_t), intent(inout), target :: this

procedure, public :: switch_forces => mbd_calc_switch_forces

private subroutine mbd_calc_switch_forces(this, forces)

Update whether to calculate forces.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(inout)			::	this
logical,	intent(in)			::	forces	Whether to calcualte forces.

procedure, public :: update_coords => mbd_calc_update_coords

private subroutine mbd_calc_update_coords(this, coords)

Update atomic coordinates.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(inout)			::	this
real(kind=dp),	intent(in)			::	coords(:,:)	( $3\times N$ , a.u.) New atomic coordinates.

procedure, public :: update_lattice_vectors => mbd_calc_update_lattice_vectors

private subroutine mbd_calc_update_lattice_vectors(this, latt_vecs)

Update unit-cell lattice vectors.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(inout)			::	this
real(kind=dp),	intent(in)			::	latt_vecs(:,:)	( $3\times 3$ , a.u.) New lattice vectors in columns.

procedure, public :: update_vdw_params_custom => mbd_calc_update_vdw_params_custom

private subroutine mbd_calc_update_vdw_params_custom(this, alpha_0, C6, r_vdw)

Update vdW parameters in a custom way.

Arguments

Type	Intent		Name
class(mbd_calc_t),	intent(inout)	::	this
real(kind=dp),	intent(in)	::	alpha_0(:)	(a.u.) New atomic static polarizabilities.
real(kind=dp),	intent(in)	::	C6(:)	(a.u.) New atomic $C_6$ coefficients.
real(kind=dp),	intent(in)	::	r_vdw(:)	(a.u.) New atomic vdW radii.

procedure, public :: update_vdw_params_from_ratios => mbd_calc_update_vdw_params_from_ratios

private subroutine mbd_calc_update_vdw_params_from_ratios(this, ratios)

Update vdW parameters based on scaling of free-atom values.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(inout)			::	this
real(kind=dp),	intent(in)			::	ratios(:)	Ratios of atomic volumes in the system and in vacuum.

procedure, public :: update_vdw_params_nl => mbd_calc_update_vdw_params_nl

private subroutine mbd_calc_update_vdw_params_nl(this, alpha_0_ratios, C6_ratios)

Update vdW parameters for the MBD-NL method.

Arguments

Type	Intent		Name
class(mbd_calc_t),	intent(inout)	::	this
real(kind=dp),	intent(in)	::	alpha_0_ratios(:)	Ratios of free-atom exact static polarizabilities and those from the VV functional.
real(kind=dp),	intent(in)	::	C6_ratios(:)	Ratios of free-atom exact $C_6$ coefficients and those from the VV functional.

procedure, public :: evaluate_vdw_method => mbd_calc_evaluate_vdw_method

private subroutine mbd_calc_evaluate_vdw_method(this, energy)

Evaluate a given vdW method for a given system and vdW parameters, retrieve energy.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(inout)			::	this
real(kind=dp),	intent(out)			::	energy	(a.u.) VdW energy.

procedure, public :: get_gradients => mbd_calc_get_gradients

private subroutine mbd_calc_get_gradients(this, gradients)

Retrieve nuclear energy gradients if they were requested in the MBD input.

The gradients are calculated together with the energy, so a call to this method must be preceeded by a call to evaluate_vdw_method. For the same reason, the gradients must be requested prior to this called via calculate_forces.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(in)			::	this
real(kind=dp),	intent(out)			::	gradients(:,:)	( $3\times N$ , a.u.) Energy gradients, $\mathrm dE/\mathrm d\mathbf R_i$ , index $i$ runs over columns.

procedure, public :: get_vdw_params_ratios_gradients => mbd_calc_get_vdw_params_ratios_gradients

private subroutine mbd_calc_get_vdw_params_ratios_gradients(this, dE_dratios)

Get gradients of the energy w.r.t. Hirshfeld ratios if they were requested in the MBD input.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(inout)			::	this
real(kind=dp),	intent(out)			::	dE_dratios(:)	Gradients of the energy w.r.t. Hirshfeld ratios.

procedure, public :: get_lattice_derivs => mbd_calc_get_lattice_derivs

private subroutine mbd_calc_get_lattice_derivs(this, latt_derivs)

Provide lattice-vector energy gradients if they were requested in the MBD input.

The gradients are actually calculated together with the energy, so a call to this method must be preceeded by a call to evaluate_vdw_method. For the same reason, the gradients must be requested prior to this called via calculate_forces.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(in)			::	this
real(kind=dp),	intent(out)			::	latt_derivs(:,:)	( $3\times 3$ , a.u.) Energy gradients, $\mathrm dE/\mathrm d\mathbf a_i$ , index $i$ runs over columns.

procedure, public :: get_lattice_stress => mbd_calc_get_lattice_stress

private subroutine mbd_calc_get_lattice_stress(this, stress)

Provide stress tensor of the lattice.

This is a utility function wrapping get_lattice_derivs. The lattice vector gradients are coverted to the stress tensor.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(in)			::	this
real(kind=dp),	intent(out)			::	stress(:,:)	( $3\times 3$ , a.u.) Stress tensor.

procedure, public :: get_spectrum_modes => mbd_calc_get_spectrum_modes

private subroutine mbd_calc_get_spectrum_modes(this, spectrum, modes)

Provide MBD spectrum if it was requested in the MBD input.

The spectrum is actually calculated together with the energy, so a call to this method must be preceeded by a call to evaluate_vdw_method. For the same reason, the spectrum must be requested prior to this call via calculate_spectrum.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(inout)			::	this
real(kind=dp),	intent(out)			::	spectrum(:)	( $3N$ , a.u.) Energies (frequencies) of coupled MBD modues, $\omega_i$ .
real(kind=dp),	intent(out),	optional	allocatable	::	modes(:,:)	( $3N\times 3N$ ) Coupled-mode wave functions (MBD eigenstates), $\psi_j$ , in the basis of uncoupled states, $C_{ij}=\langle\phi_i\|\psi_j\rangle$ , index $j$ runs over columns. To save memory, the argument must be allocatable, and the method transfers allocation from the internal state to the argument. For this reason, the method can be called only once wih this optional argument per calculation.

procedure, public :: get_rpa_orders => mbd_calc_get_rpa_orders

private subroutine mbd_calc_get_rpa_orders(this, rpa_orders)

Provide RPA orders if they were requested in the MBD input.

The orders are actually calculated together with the energy, so a call to this method must be preceeded by a call to evaluate_vdw_method. For the same reason, the spectrum must be requested prior to this call via do_rpa and rpa_orders.

Arguments

Type	Intent	Optional	Attributes		Name
class(mbd_calc_t),	intent(inout)			::	this
real(kind=dp),	intent(out),		allocatable	::	rpa_orders(:)	(a.u.) MBD energy decomposed to RPA orders.

procedure, public :: get_exception => mbd_calc_get_exception

private subroutine mbd_calc_get_exception(this, code, origin, msg)

Retrieve an exception in the MBD calculation if it occured.

Arguments

Type	Intent		Name
class(mbd_calc_t),	intent(inout)	::	this
integer,	intent(out)	::	code	Exception code, values defined in mbd_constants.
character(len=*),	intent(out)	::	origin	Exception origin.
character(len=*),	intent(out)	::	msg	Exception message.

mbd_calc_t Derived Type

Contents

Type-Bound Procedures

type, public :: mbd_calc_t

Contents

Type-Bound Procedures

Type-Bound Procedures

procedure, public :: init => mbd_calc_init

private subroutine mbd_calc_init(this, input)

Arguments

procedure, public :: destroy => mbd_calc_destroy

private subroutine mbd_calc_destroy(this)

Arguments

procedure, public :: switch_forces => mbd_calc_switch_forces

private subroutine mbd_calc_switch_forces(this, forces)

Arguments

procedure, public :: update_coords => mbd_calc_update_coords

private subroutine mbd_calc_update_coords(this, coords)

Arguments

procedure, public :: update_lattice_vectors => mbd_calc_update_lattice_vectors

private subroutine mbd_calc_update_lattice_vectors(this, latt_vecs)

Arguments

procedure, public :: update_vdw_params_custom => mbd_calc_update_vdw_params_custom

private subroutine mbd_calc_update_vdw_params_custom(this, alpha_0, C6, r_vdw)

Arguments

procedure, public :: update_vdw_params_from_ratios => mbd_calc_update_vdw_params_from_ratios

private subroutine mbd_calc_update_vdw_params_from_ratios(this, ratios)

Arguments

procedure, public :: update_vdw_params_nl => mbd_calc_update_vdw_params_nl

private subroutine mbd_calc_update_vdw_params_nl(this, alpha_0_ratios, C6_ratios)

Arguments

procedure, public :: evaluate_vdw_method => mbd_calc_evaluate_vdw_method

private subroutine mbd_calc_evaluate_vdw_method(this, energy)

Arguments

procedure, public :: get_gradients => mbd_calc_get_gradients

private subroutine mbd_calc_get_gradients(this, gradients)

Arguments

procedure, public :: get_vdw_params_ratios_gradients => mbd_calc_get_vdw_params_ratios_gradients

private subroutine mbd_calc_get_vdw_params_ratios_gradients(this, dE_dratios)

Arguments

procedure, public :: get_lattice_derivs => mbd_calc_get_lattice_derivs

private subroutine mbd_calc_get_lattice_derivs(this, latt_derivs)

Arguments

procedure, public :: get_lattice_stress => mbd_calc_get_lattice_stress

private subroutine mbd_calc_get_lattice_stress(this, stress)

Arguments

procedure, public :: get_spectrum_modes => mbd_calc_get_spectrum_modes

private subroutine mbd_calc_get_spectrum_modes(this, spectrum, modes)

Arguments

procedure, public :: get_rpa_orders => mbd_calc_get_rpa_orders

private subroutine mbd_calc_get_rpa_orders(this, rpa_orders)

Arguments

procedure, public :: get_exception => mbd_calc_get_exception

private subroutine mbd_calc_get_exception(this, code, origin, msg)

Arguments