12.4.1.4.3. crfit

Charge-response parametrization of a molecule with xtpdft: the charge-response matrix Pi (Hirshfeld charges), the molecular polarizability and the residual polarizabilities, from the static response to Hirshfeld-localized potentials and uniform fields (coupled-perturbed Kohn-Sham, or finite differences of SCFs). Reads job_name.xyz; closed-shell molecules. The following table contains the defaults input options for the calculator, The default OPTIONAL means this option is switched off, if no input is given. REQUIRED arguments have to be specified, otherwise an error is thrown.

Property Name	Default Value	Description	Valid Input
job_name	system	Input file name without extension, also used for intermediate files
dftpackage.name	xtp	Name of the DFT package	xtp orca
dftpackage.charge	0	Molecular charge	int
dftpackage.spin	1	Molecular multiplicity	int+
dftpackage.basisset	def2-tzvp	Basis set for MOs
dftpackage.auxbasisset	OPTIONAL	Auxiliary basis set for RI
dftpackage.externalfield	OPTIONAL	Field given in x y z components
dftpackage.executable	OPTIONAL	Path to executable for dftpackage
dftpackage.ecp	OPTIONAL	Effective Core Potentials for DFT Calculations
dftpackage.optimize	false	Perform a molecular geometry optimization	bool
dftpackage.functional	XC_HYB_GGA_XC_PBEH	Exchange correlation functional used. You can also specify an exchange and a correlation functional
dftpackage.scratch	/tmp/qmpackage	path to the scratch folder
dftpackage.polarization	false	Calculate polarisation	bool
dftpackage.dipole_spacing	0.1	Spacing for splitting multipoles into charges	float+
dftpackage.temporary_file	temp	Filename for temporary files without extension
dftpackage.convergence_tightness	tight	How accurate the dft self-consistency has to be	low normal tight verytight
dftpackage.cleanup		files to remove after the calculation. Specify the fileextensions
dftpackage.initial_guess	atom	Method to use to make initial guess, independent(electrons) or atom(densities) or previous calculation keyword orbfile or dimer_guess (combine two monomer .orb files, see dimer_guess_orbA/orbB below; closed-shell monomers work for restricted and unrestricted runs, open-shell monomers need the unrestricted path)	independent atom orbfile huckel huckel_dft dimer_guess
dftpackage.dimer_guess_orbA		Converged .orb file of monomer A, read only for initial_guess=dimer_guess. Its atoms must match the first N_A atoms of the molecule in internal geometry; translation and rotation are allowed.
dftpackage.dimer_guess_orbB		As dimer_guess_orbA, for monomer B, matching the remaining atoms of the molecule.
dftpackage.orca		orca specific keywords can be added here, where the xml tag corresponds to the option and the value to the option’s value
dftpackage.xtpdft.dft_in_dft.activeatoms		Indices of atoms in active region
dftpackage.xtpdft.dft_in_dft.threshold	0.4	Mulliken population above which orbital is considered in the active region
dftpackage.xtpdft.dft_in_dft.levelshift	10000.0	Levelshift energy for the projection operator
dftpackage.xtpdft.dft_in_dft.truncate_basis	false	Truncate the basis-set to active atoms only	bool
dftpackage.xtpdft.dft_in_dft.truncation_threshold	1e-4	Threshold to convert an inactive atom to a border atom	float+
dftpackage.xtpdft.screening_eps	1e-9	screening eps	float+
dftpackage.xtpdft.overlap_tolerance	1e-8	Eigenvalues of the AO overlap matrix below this value are removed from the orthogonalization (near linear dependencies; the removed directions become zero orbitals at the top of the spectrum). Raise to 1e-7 to 1e-6 if the log reports a nearly singular overlap and the SCF is unstable.	float+
dftpackage.xtpdft.ri_pair_threshold	1e-10	RI only: basis-function shell pairs whose three-centre integrals (P|ab) are bounded by less than this (Schwarz bound) are not stored. Reduces the memory of the stored RI tensor substantially for large molecules; energies change at the level of the threshold. 0 stores all pairs.	float+
dftpackage.xtpdft.fock_matrix_reset	5	how often the fock matrix is reset	int+
dftpackage.xtpdft.integration_grid	medium	vxc grid quality	xcoarse coarse medium fine xfine
dftpackage.xtpdft.force_uks_path	false	forcing UKS path	bool
dftpackage.xtpdft.polarizability	false	After the SCF, compute the static dipole polarizability tensor analytically (coupled-perturbed Kohn-Sham with the three dipole operators; closed-shell states, LDA/GGA/global hybrids) and store it in the orb (HDF5) file, e.g. as the target for molpol (qmpackage xtp).	bool
dftpackage.xtpdft.compute_forces	false	Compute analytic ground-state DFT nuclear forces (RI, and hybrid exchange for UKS) and store them in the orb (HDF5) file. Adds cost to every converged SCF.	bool
dftpackage.xtpdft.cdft.enabled	false	Enable a CDFT charge constraint on this calculation	bool
dftpackage.xtpdft.cdft.indices		Indices (0-based) of the atoms in the constrained fragment, in the range syntax of the diabatization fragments, e.g. ‘1 3 13:17’
dftpackage.xtpdft.cdft.charge	0.0	Target charge of the fragment relative to the neutral fragment (sum of its nuclear charges): +1.0 removes one electron, -1.0 adds one.	float
dftpackage.xtpdft.cdft.initial_lambda	0.0	Initial guess for the Lagrange multiplier lambda, the centre of the initial bisection bracket	float
dftpackage.xtpdft.cdft.population_tolerance	1e-4	Convergence criterion of the outer loop: maximum deviation of the fragment population from the target, in electrons	float+
dftpackage.xtpdft.cdft.max_iterations	50	Maximum number of outer (bisection) iterations, each a full inner SCF	int+
dftpackage.xtpdft.cdft.guess_strategy	warmstart	Start guess of the inner SCF for each bisection trial after the first. warmstart: the converged MOs of the preceding trial (usually faster, since consecutive lambdas are close); fresh: the top-level initial_guess, which can help if consecutive trials have very different electronic structures.	warmstart fresh
dftpackage.xtpdft.convergence.energy	1E-7	DeltaE at which calculation is converged	float+
dftpackage.xtpdft.convergence.method	DIIS	Main method to use for convergence accelertation	DIIS mixing
dftpackage.xtpdft.convergence.DIIS_start	0.002	DIIS error at which DIIS takes over	float+
dftpackage.xtpdft.convergence.ADIIS_start	0.8	DIIS error at which ADIIS takes over	float+
dftpackage.xtpdft.convergence.DIIS_length	20	old hamiltonians to keep in history	int+
dftpackage.xtpdft.convergence.DIIS_maxout	false	if true remove the maximum element in the history if DIIS_length is exceeded.Otherwise, the oldest element is removed.	bool
dftpackage.xtpdft.convergence.levelshift	0.0	levelshift to apply to hamiltonian	float+
dftpackage.xtpdft.convergence.levelshift_end	0.2	DIIS error at levelshifting is disabled	float+
dftpackage.xtpdft.convergence.max_iterations	100	max iterations to use	int+
dftpackage.xtpdft.convergence.error	1e-7	convergence error	float+
dftpackage.xtpdft.convergence.mixing	0.7	mixing parameter for linear mixing of density matrices	float+
dftpackage.xtpdft.convergence.mixing_end	0.8	DIIS error below which linear mixing is switched off. Independent of ADIIS_start (like ORCA’s DampErr), so difficult systems can keep mixing after (A)DIIS starts; the default equals that of ADIIS_start.	float+
dftpackage.xtpdft.convergence.mixing_max	0.98	Upper limit to which the mixing parameter is raised linearly with consecutive ADIIS failures (UKS path), like ORCA’s DampMax.	float+
dftpackage.xtpdft.convergence.energy_reset	1.0	If the energy rises by more than this above the lowest energy reached so far, the (A)DIIS history is discarded and the SCF restarts, damped, from the lowest-energy density. 0 disables.	float+
dftpackage.xtpdft.convergence.second_order	auto	Second-order (trust-region augmented Hessian, TRAH) SCF steps. auto: switch to them when (A)DIIS fails repeatedly or the DIIS error stalls, then use them until convergence; always: use them from the first iteration; off: never. Exact analytic orbital Hessian for RKS and UKS (LDA/GGA and global hybrids; spin-polarized f_xc for UKS); for UKS with a functional without second derivatives in libxc, finite differences of the Fock matrix (two Fock builds per Hessian product).	auto always off
dftpackage.xtpdft.convergence.davidson_max_iter	50	Maximum number of micro-iterations (Hessian products) per second-order (TRAH) step.	int+
method	analytic	analytic: coupled-perturbed Kohn-Sham (LDA, GGA, global hybrids); finite_differences: two SCFs per perturbation	analytic finite_differences
tolerance	1e-7	analytic: relative residual of the coupled-perturbed equations	float+
step	1e-3	finite_differences: strength of each perturbation: Hirshfeld-localized potential in Hartree, uniform field in Hartree/bohr	float+
scf_error	1e-9	Every SCF is converged to at least this DIIS error (and 1/100 of it in the energy): the ground state for both methods, and the perturbed SCFs, whose densities are differenced, for finite_differences	float+
inversion	true	If the geometry has an inversion centre (equivalent atoms within 1e-4 bohr), perturb only one atom of each pair and obtain the other response by symmetry	bool
mpsfile	OPTIONAL	Template .mps of the molecule with the permanent multipoles (same atoms in the same order); if given, output.mps is written with the residual polarizabilities on its P lines, rotated into the template frame
output	OPTIONAL	Output prefix: output.crm, output.json (the keys of xtp_cr_fit, readable by xtp_cr_mps) and, with mpsfile, output.mps

Note

An xml file containing the defaults for the crfit calculator can be created via -p crfit -o FILENAME command line options `