Hello. I'm trying to do a 'vc-relax' calculation of germanium in quantum espresso. Problem is, after commending in terminal is shows the following error -
vcsmd: a positive value for cell mass is required.
I've attached both input and output file. Please take a look and tell me what to change in input file.
Hi,
You need to specify the number of atoms you have in the unit cell. This is done through the variable
nat
in the &SYSTEM cart
Also you are using a value of degauss that is quite low -- consider using a larger value and study its converge or you might risk to run an expensive calculation.
All the best.
Roberto
@Robarto D'Agosta okay... Can you please suggest me the range of degauss ... Like less than 1 or nearly 100 or something?
Degauss should be positive and less than 1. I would start with something around 0.01 and then decrease it. Plot the total energy of the relaxed structure against it to do the convergence test... Usually two or three values should be able to give you the idea of which value to select.
Regards,
Roberto
- Badges
- Science topic
- Similar topics
- Filing