DFTB+ General Format (gen)

Overview

Property Value
File extension .gen
Coordinate units Ångström (Cartesian) or fractional
Supports periodicity Yes (0D, 3D, helical)
Supports bonds No
Format hint gen

Specification

Note

Reference

The general (gen) format is the standard geometry input format for DFTB+. It is based on the xyz format.

Format Structure

Line 1: Number of atoms and geometry type

Type Code Description Coordinates
Cluster C Non-periodic molecule Ångström
Supercell S 3D periodic with Cartesian Ångström
Fractional F 3D periodic with fractional Lattice fractions
Helical H Helical symmetry Ångström

Line 2: Element symbols (space-separated), indexed starting from 1

Atom lines: index element_index x y z - First integer is currently ignored - Second integer references element symbol in line 2

Periodic systems (S, F, H): Additional lines after atoms: - Origin (3 reals) - Three lattice vectors (3 lines × 3 reals)

Lines starting with # are comments.

Examples

Molecular System (Cluster)

Caffeine molecule:

24 C
 C N O H
    1    1    1.07317000000000E+00    4.88500000000000E-02   -7.57300000000000E-02
    2    2    2.51365000000000E+00    1.25600000000000E-02   -7.58000000000000E-02
    3    1    3.35199000000000E+00    1.09592000000000E+00   -7.53300000000000E-02
    4    2    4.61898000000000E+00    7.30280000000000E-01   -7.54900000000000E-02
    5    1    4.57907000000000E+00   -6.31440000000000E-01   -7.53100000000000E-02
    6    1    3.30131000000000E+00   -1.10256000000000E+00   -7.52400000000000E-02
    7    1    2.98068000000000E+00   -2.48687000000000E+00   -7.37700000000000E-02
    8    3    1.82530000000000E+00   -2.90038000000000E+00   -7.57700000000000E-02
    9    2    4.11440000000000E+00   -3.30433000000000E+00   -6.93600000000000E-02
   10    1    5.45174000000000E+00   -2.85618000000000E+00   -7.23500000000000E-02
   11    3    6.38934000000000E+00   -3.65965000000000E+00   -7.23200000000000E-02
   12    2    5.66240000000000E+00   -1.47682000000000E+00   -7.48700000000000E-02
   13    1    7.00947000000000E+00   -9.36480000000000E-01   -7.52400000000000E-02
   14    1    3.92063000000000E+00   -4.74093000000000E+00   -6.15800000000000E-02
   15    4    7.33980000000000E-01    1.08786000000000E+00   -7.50300000000000E-02
   16    4    7.12390000000000E-01   -4.56980000000000E-01    8.23350000000000E-01
   17    4    7.12400000000000E-01   -4.55800000000000E-01   -9.75490000000000E-01
   18    4    2.99301000000000E+00    2.11762000000000E+00   -7.47800000000000E-02
   19    4    7.76531000000000E+00   -1.72634000000000E+00   -7.59100000000000E-02
   20    4    7.14864000000000E+00   -3.21820000000000E-01    8.19690000000000E-01
   21    4    7.14802000000000E+00   -3.20760000000000E-01   -9.69530000000000E-01
   22    4    2.86501000000000E+00   -5.02316000000000E+00   -5.83300000000000E-02
   23    4    4.40233000000000E+00   -5.15920000000000E+00    8.28370000000000E-01
   24    4    4.40017000000000E+00   -5.16929000000000E+00   -9.47800000000000E-01

3D Periodic System (Supercell)

Ammonia molecular crystal:

16 S
 H N
    1    1    2.19855889440000E+00    1.76390058240000E+00    8.80145481600000E-01
    2    1    1.76390058240000E+00    8.80145481600000E-01    2.19855889440000E+00
    3    1    8.80145481600000E-01    2.19855889440000E+00    1.76390058240000E+00
    4    1    4.84115108400000E+00    1.61941554720000E+00    4.93981400880000E+00
    5    1    4.35630903840000E+00    2.49981169680000E+00    3.63248012160000E+00
    6    1    3.51957925440000E+00    1.15357413600000E+00    4.08403345680000E+00
    7    1    4.08403345680000E+00    3.51957925440000E+00    1.15357413600000E+00
    8    1    4.93981400880000E+00    4.84115108400000E+00    1.61941554720000E+00
    9    1    3.63248012160000E+00    4.35630903840000E+00    2.49981169680000E+00
   10    1    2.49981169680000E+00    3.63248012160000E+00    4.35630903840000E+00
   11    1    1.15357413600000E+00    4.08403345680000E+00    3.51957925440000E+00
   12    1    1.61941554720000E+00    4.93981400880000E+00    4.84115108400000E+00
   13    2    1.37461317840000E+00    1.37461317840000E+00    1.37461317840000E+00
   14    2    3.99815460000000E+00    1.99105592400000E+00    4.46364507600000E+00
   15    2    4.46364507600000E+00    3.99815460000000E+00    1.99105592400000E+00
   16    2    1.99105592400000E+00    4.46364507600000E+00    3.99815460000000E+00
    0.00000000000000    0.00000000000000    0.00000000000000
    5.01336000000000    0.00000000000000    0.00000000000000
    0.00000000000000    5.01336000000000    0.00000000000000
    0.00000000000000    0.00000000000000    5.01336000000000

Limitations

The implementation of this format is (to our knowledge) feature-complete.

Note

Feel free to bring missing features to our attention by opening an issue.