TOMBO Ver.2 Manual

3.3 KPOINT.inp 38
3.2.42 Mcheb
Number of Chebyshev polynomials for fitting AO potential in atomic spheres. Default
value of MCheb is 30.
3.2.43 nStep
Maximum number of MD (or Relaxation or TDDFT) steps. Default value of nStep is 1.
3.2.44 singlet, triplet
Initial guess for the singlet and triplet optical gaps.
In solving the Bethe–Salpeter equation to obtain photoabsorption spectra, an initial
guess for optical gap ("singlet" and "triplet") must be given in units of [eV]. "singlet" is
a value for the singlet exciton, and "triplet" is a value for the triplet exciton. Default values
are singlet = 0.d0 and triplet = 0.d0.
3.3 KPOINT.inp
In a crystal calculation (iCry = 1), user has to define k points (usually on symmetry
lines) for the energy-band outputs. For each band, a list of energies of all the k points are
given by "band_0001.out", "band_0002.out", .... The total list including all bands is given
by band.out. Form of KPOINT.inp is given in Table 3.5.
Table 3.5 Form of KPOINT.inp file
line 1 Direct/Cartesian
line 2 numbers of k points for "out+sum", "out", and "sum"
line 3 1 st k point and weight
line 4 2 nd k point and weight
line 5 3 rd k point and weight
line 6 ... ...
line 7 n th k point and weight
For a three-dimensional lattice defined by its primitive vectors (a 1 , a 2 , a 3 ), the reciprocal
lattice is generated by its three reciprocal primitive defined by the formulae
a 2 × a 3
b 1 = 2π
a 1 · (a 2 × a 3 ) ,
b a 3 × a 1
2 = 2π
a 2 · (a 3 × a 1 ) ,
b a 1 × a 2
3 = 2π
a 3 · (a 1 × a 2 ) . (3.3)