## DFTB

Perform a DFTB calculation

SCC

The self-consistent charge variant of DFTB. The default is non-SCC.

MEMOSCC

use previous atomic charges to restart the SCC process at a new geometry. This keyword automatically set SCC calculation (even without SCC keyword)

TOL=

The SCC convergence criterion in electron charges. The default is 1.0E-8.

DIAG=

User-specified diagonalisation routine for the generalised Eigen value systems. The method is specified after the ’=’. Legal options are DSYGVD, DSYGV, DSYGVR, SOM.

ETOL=

Requested energy tolerance for iterative solvers of the total energy (used for CPBO, see CARPAR section)

MAX=

Maximum number of SCC cycles. The default is 100

MIX=

Mixing value for simple and Broyden mixing. The default is 0.2. This value is independent from the DFT mixing value

SIMPLE

Simple mixing instead of Broyden convergence acceleration is performed for SCC. This is per default switched off

L-DEP

Angular momentum resolved SCC. Here, the self-consistent charge procedure is applied to Mulliken shell charges rather than to Mul- liken atomic charges.By default, this option is deactivated.FERMI=

As FERMI, but with used-specified Fermi temperature (in K) following the keyword.

FERMI

The electron occupation follows a Fermi distribution

THIRD

Third order DFTB; The running directory should contain a file names 3ord_param for 3rd order derivatives parameters, each line being like H -0.1857, recomended to be used with GCOR (reference Gauss et al. JCTC, 011, 7, 931

GCOR=

Correction for gamma function for short range; value for Zeta provided after GCOR= (reference Gauss et al. JCTC, 011, 7, 931

DISP=

London dispersion with a damping function. By default this option is switched off. DISP=1 Zhechkov et al., JCTC 2005 DISP=2 : Rapacioli et al., JCP, 2009

DISP

Equivalent to DISP=1. By default this option is switched off.

CONST=

Perform charge constrained DFTB calculation, the number after "=" specifies the subsystem on which the charge is localised

CONST

Perform charge constrained DFTB calculation.

NMOL=

Specifies the number of subsystems for constrained or CI-DFTB calculation

CI

Perform DFTB+CI calculation (to be used with CONST and SIZECI keywords). By default of diagonal terms are computed with the overlaps between SLATER determinents (not using the HOMO approximation).

NOSLAT

Compute CI matrices assuming that only the HOMO orbitals are involved instead of computing matrices elements with slater determinants.

SIZECI=

Specifies the size of the CI matrix for DFTB-CI calculation.

LEV_S=

Use level-shift for the SCC convergency

CM3POT

Use CM3 charges instead of Mulliken charge for all the system. CM3 parameter defined by BONDPARAM keyword

WMUL

Weight the Mulliken distribution, the weights are fixed by parameters defined byu BONDPARAM keyword

EPSMUL

Weight the Mulliken distribution, the weight is epsii/(epsii+epsjj)

LRESP

Perform a TDDFTB calculation (Linear response)