1
2! Unit cell optimisation for Ge with the PBE functional. This is performed with
3! geometric optimisation in which the lattice vectors are changed.
4
5! Setting 'latvopt' to 1 performs full unconstrained optimisation of the lattice
6! vectors. Setting it to 2 results in an iso-volumetric optimisation. In both
7! cases, the atomic positions are also optimised. To constrain the atomic
8! positions, set the nuclear mass to be a negative number in the species file.
9
10! As the calculation progresses, you can plot the files TOTENERGY_OPT.OUT and
11! STRESSMAX.OUT to see the change in the total energy and stress tensor. The
12! modulus of the maximum force on the atoms is written to FORCEMAX.OUT.
13
14! The updated unit cell geometry is written to GEOMETRY_OPT.OUT. The last entry
15! in this file contains the final lattice parameters and atomic positions.
16
17tasks
18  2
19
20! unconstrained optimisation of the lattice vectors
21latvopt
22  1
23
24mixtype
25  3
26
27! switch on high-quality parameters for accurate stress tensors
28highq
29 .true.
30
31! switch off automatic determination of the k-point grid
32autokpt
33 .false.
34
35ngridk
36  4 4 4
37
38! PBE exchange-correlation functional
39xctype
40  20
41
42avec
43  1.0  1.0  0.0
44  1.0  0.0  1.0
45  0.0  1.0  1.0
46
47scale
48  5.3451
49
50sppath
51  '../../../species/'
52
53atoms
54  1                                 : nspecies
55  'Ge.in'                           : spfname
56  2                                 : natoms; atposl below
57  0.0   0.0   0.0
58  0.25  0.25  0.25
59
60