Why is my plot of 'Total Energy vs Energy cut off' is jagged. Previously ecutwfc was kept at 40, 60 and now 80. But still I am unable to figure why isn't it converging. Where as 'Total Energy vs K points' show convergent behavior.
&CONTROL
calculation = 'scf' ,
restart_mode = 'from_scratch' ,
outdir = '../../tmp' ,
pseudo_dir = '../../pseudo' ,
prefix = 'Pt' ,
/
&SYSTEM
ibrav = 2,
celldm(1) = 7.5828,
nat = 1,
ntyp = 1,
ecutwfc = 80 ,
occupations = 'smearing' ,
degauss = 0.02 ,
smearing = 'mp' ,
/
&ELECTRONS
/
&IONS
/
&CELL
cell_dynamics = 'bfgs' ,
/
ATOMIC_SPECIES
Pt 195.07800 Pt.pbe-nd-rrkjus.UPF
ATOMIC_POSITIONS alat
Pt 0.000000000 0.000000000 0.000000000
K_POINTS automatic
8 8 8 0 0 0
Edit 1:
Changing 'ecutwfc' ranging between 6-40 in the intervals of 2 gives very good convergence.
Why doesn't this happen in other plot where it ranges from 20-80 in the intervals of 1?