Hi all,
I am trying to figure out whether there is a way to scale all three unit cell
vectors at once in QE using pw.x. In my input file, I am using the
CELL_PARAMETERS card (in units of Angstrom) to specify a unit cell. This
(https://www.mail-archive.com/[email protected]/msg19387.html)
old post seems to suggest that the 'A' parameter in the &SYSTEM section acts as
a scaling parameter if 'ibrav==0' and the CELL_PARAMETERS card is used to
specify the lattice. I take this to mean that each lattice vector is multiplied
by *A, where A is a dimensionless number. However, QE complains that:
"Error in routine cell_base_init (2):
lattice parameter specified twice"
I've tried specifying the atomic positions in 'crystal' (fractional)
coordinates and in Angstroms but to no use. Input file is attached below. I'm
using QE version 6.4.1.
Is the interpretation of A as a scaling parameter with these settings
deprecated, or am I missing something?
Thanks in advance,
Siebe
input file:
&CONTROL
title = 'cha' ,
calculation = 'scf' ,
wf_collect = .true. ,
etot_conv_thr = 1.0D-6 ,
/
&SYSTEM
ibrav = 0,
A = 1.2,
nat = 108,
ntyp = 2,
ecutwfc = 100 ,
nosym = .true. ,
/
&ELECTRONS
scf_must_converge = .true. ,
/
CELL_PARAMETERS angstrom
13.738516409 -0.000070574 0.000007978
-6.869319180 11.897869408 -0.000009602
0.000010055 -0.000007302 14.715552482
ATOMIC_SPECIES
O 15.99940 O.pbe-rrkjus.UPF
Si 28.08551 Si.pbe-rrkj.UPF
ATOMIC_POSITIONS crystal
O 0.901932010 0.098069851 0.126854702
O 0.098068745 0.901933544 0.873144107
O 0.901940529 0.803877937 0.126862649
O 0.098062465 0.196127742 0.873139246
(...)
K_POINTS gamma
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