When I run the program there are no results in the output file, and in the err file this message appears:
Initialization of occ, with occopt= 1
There are not enough bands to get charge balance right
Action: modify input file ...
(check the pseudopotential charges, the variable charge,
and the declared number of bands, nband)
I'm using occopt = 1 because I know is the value used for semiconductors, my question is:
How can I know the number of bands needed for a given element? In this case im using Si, but if I were using Co, Fe, or Cu how could I know?
here is the code I am doing:
Code: Select all
#I want an ecut convergence study
#Im simulating an isolated Si molecule, as done in I and II but with parameters for Si.
#Doing a double loop, with 10 data sets, one for the molecule and the other one for the isolated atom, im trying to reach ecut = 12, from ecut = 2 with steps with ecut =1.
ndtset 10 udtset 5 2
#Here i define the ecut and acell, later i will optimize acell.
acell 10 10 10
ecut:? 2 ecut+? 1
#First data set, Find the best bond lenght for a Si molecule, and its asociated total energy.
natom?1 2 # There are two atoms
ionmov?1 2 # Use the modified Broyden algorithm
ntime?1 10 # Maximum number of Broyden "timesteps"
tolmxf?1 5.0d-5 # Stopping criterion for the geometry optimization : when
# the residual forces are less than tolmxf, the Broyden
# algorithm can stop
xcart?1 -0.5 0.0 0.0 # The starting values of the
0.5 0.0 0.0 # atomic coordinates
toldff?1 5.0d-6 # Will stop the SCF cycle when, twice in a row,
# the difference between two consecutive evaluations of
# forces differ by less than toldff (in Hartree/Bohr)
nband?8 8 # Just one band
#Second data set: To obtain the isolated atom total energy.
natom?2 1 # There is one atom
nsppol?2 2 # Spin-polarized calculation
nband?2 1 1 # Number of bands for spin up and spin down
toldfe?2 1.0d-6 # Will stop the SCF cycles when, twice in a row,
# the difference between two consecutive evaluations
# of total energy differ by less than toldfe (in Hartree)
# This value is way too large for most realistic studies of materials
xcart?2 0.0 0.0 0.0 # The atom is located at the origin
spinat?2 0.0 0.0 1.0 # Initialisation of spin
rprim 0.0 0.5 0.5
0.5 0.0 0.5
0.5 0.5 0.0
#Types of atoms definition:
typat 1 1
# K Points Grid Definition.
kptopt 0 #Meter manualmente los puntos.
nkpt 1 #Sólo un punto k es necesario para un sistema aislado
#SCF procedure definition:
# El toldfe se definió arriba.
Thank you very much