Last Modified 27 March 2002
The sctb code has three required input files, one that is required by some programs, and two optional input files.
All of the codes get their configuration information from standard
input. The format for all of the eval_energy.*,
eval_forces.*, and eval_virial.*
programs is:
N_CONFIGS
<geometry of config 1>
<geometry of config 2>
.
.
.
<geometry of config (N_CONFIGS)>
A geometry consists of
N_ATOMS
a_1_x a_1_y a_1_z
a_2_x a_2_y a_2_z
a_3_x a_3_y a_3_z
p_1_x p_1_y p_1_z atomic_num_1
p_2_x p_2_y p_2_z atomic_num_2
.
.
.
p_(N_ATOMS)_x p_(N_ATOMS)_y p_(N_ATOMS)_z atomic_num_(N_ATOMS)
where All supercell and position vectors must be specified in units that are compatible with the TB model. All of the NRL-TB models assume input is in Angstroms.
eval_second_derivs.* and both
test_forces.* and test_virial.*
read a line containing
dx, a variable defining the size of the step
for the finite difference, before reading N_CONFIGS
from stdin.
The tightbind.parms.NRL_TB file is the basic parameter
file for the sctb package. It's format is almost
identical to the
parameter file
for the
static code.
The only exception is that on the 6'th line, where the original
parameter files list the atomic weight, the sctb
package codes require the weight followed by the atomic
number, on the same line.
The tightbind.parms.self_cons file is the parameter
file governing charge-self-consistency for the sctb package.
If present, charge self-consistency is used. Its format is:
do_interatomic
N_types
atomic_num_1 U_1
atomic_num_2 U_2
.
.
.
atomic_num_N_types U_N_types
The tb.data file contains misc. information needed
to do the tight-binding calculation. Its format is:
1.0D-2
3 3 1
0
The k-point mesh file k_pt_mesh.data is required
by the *.nrl_tb_k_sum.*
programs, but not used by the *.nrl_tb.*. Its format
is:
n_k
k_1_1 k_1_2 k_1_3 k_1_weight
k_2_1 k_2_2 k_2_3 k_2_weight
.
.
.
k_(n_k)_1 k_(n_k)_2 k_(n_k)_3 k_(n_k)_weight
Inversion symmetry in the BZ can always be used.
Only calc_energy.* without self-consistency will
correctly handle k-pt meshes that have been folded using
other symmetries, since nothing is explicitly symmetrized.
The targets.data file specifies whether some atoms
are restricted in their interactions, so only interactions
with particular other atoms are included, or some interactions
are excluded. If the file isn't present, all atoms interact
with all other atoms (up to the relevant cutoff distances).
The format is:
n_targets
target_atom_1 target_value_1
target_atom_2 target_value_2
.
.
.
target_atom_(n_targets) target_value_(n_targets)