Dear QE Users, In order to calculate the total potential along one of the SnSe bonds (Se2-Sn4), I first performed a self-consistent run with the following lattice parameters.
ibrav=8, celldm(1)=21.34350847, celldm(2)=0.3628777, celldm(3)=0.38586894 Sn 0.882841736 0.250000000 0.602195343 Sn 0.617158264 0.750000000 0.102195343 Sn 0.382841736 0.250000000 0.897804657 Sn 0.117158264 0.750000000 0.397804657 Se 0.142813748 0.250000000 0.976427467 Se 0.357186252 0.750000000 0.476427467 Se 0.642813748 0.250000000 0.523572533 Se 0.857186252 0.750000000 0.023572533 I then ran pp.x with the following input: &inputpp prefix = 'SnSe' filplot = 'potential.dat' plot_num= 1 / &plot iflag=1 output_format=0 nfile = 1 filepp(1) = 'potential.dat' e1(1)=0.117158264, e1(2)=0.750000000, e1(3)= 0.397804657, x0(1)=0.357186252, x0(2)= 0.750000000, x0(3)=0.476427467, nx=100, fileout= 'VSe2_Sn4.dat’ / The bond length is 2.73A=5.16Bohr. Attached is the output of potential vs. distance. The x-axis runs from 0 to ~0.33. According to other links in the Forum, the x-axis is in atomic units. Two possibilities: 1. The distance is in Bohr. So is the pp.x code plotting from 0 to 0.33 Bohr even though the bond length is 5.16Bohr as defined by the vectors x0 and e1? 2. The distance is in alat. Then 0.33*alat=7.04Bohr. This is longer than the bond length. So what is the unit of the x-axis? Thank you, Vahid Vahid Askarpour Department of Physics and Atmospheric Science Dalhousie University, Halifax, NS, Canada
SnSe_potential.pdf
Description: SnSe_potential.pdf
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