Parameters for calculating hessian

Parameters here are for calculating hessian matrix. The hessian matrix is defined as the square matrix of second-order partial derivatives of the total energy with respect to the displacement of atomic position. Note that the dynamical matrix can be obtained by including the mass-related coefficients.

calculation.hessian.movingAtoms

key word	:	calculation.hessian.movingAtoms
possible values	:	integer array
default value	:	all atoms in the central cell for molecular or bulk
		system; no default value for system with probes
description	:	Within the whole hessian matrix, only those elements of
		the sub-matrix corresponding to the atoms listed in
		the movingAtoms will be calculated.
		Please note that the order of the atoms has been listed
		in the output file Atoms.txt, which may be different
		from original input.
an example	:	calculation.hessian.movingAtoms = [10:291]

calculation.hessian.delta

key word	:	calculation.hessian.delta
possible values	:	a double number
default value	:	0.03 au
description	:	A small displacement of atomic position used to
		calculate the hessian matrix by numerical derivatives of
		forces.
an example	:	calculation.hessian.movingAtoms = 0.1

calculation.hessian.order

key word	:	calculation.hessian.order
possible values	:	2, 3, or 5
default value	:	3
description	:	The number of points used to calculate the derivative of
		force numerically.
an example	:	calculation.hessian.order = 2

calculation.hessian.dynamicalMatrix

key word	:	calculation.hessian.dynamicalMatrix
possible values	:	true or false
default value	:	true
description	:	If true, the dynamical matrix will be calculated.
an example	:	calculation.hessian.dynamicalMatrix = true

calculation.hessian.hamiltonianDerivative

key word	:	calculation.hessian.hamiltonianDerivative
possible values	:	true or false
default value	:	true
description	:	If true, the derivative of the hamiltonian matrix will
		be calculated, which will be used in the calculation of
		electron-phonon coupling.
an example	:	calculation.hessian.hamiltonianDerivative = true