25.2.8 Keywords for `tb`

Module tb which performs GFN-xTB or GFN2-xTB extended tight binding calculations reads in the keyword $tb

$tb
  charge <number>
  gfn <method-number>
  accuracy <number>
  etemp <number>
  broydamp <number>
  maxiter <number>

The options are:

charge -1: sets the molecular total charge. ...,-2, -1, 0, 1, 2,... If not specified, a neutral input is assumed: charge 0
gfn 2: choose method, GFN-xTB (1) or GFN2-xTB (2), default is 2
accuracy 1.0: accuracy for SCC calculations, lower value means higher accuracy. Default is 1.0
etemp 300: electronic temperature in Kelvin, default is 300K
broydamp 0.4: Broyden damping for charge mixing, default is 0.4
maxiter 250: maximum number of SCC iterations, default is 250

25.2.8 Keywords for tb