[Q-e-developers] Trouble with vc-relax: "Too many g vector" error

[Mohammadreza Karamad]

Hi,

I am attempting to optimize
​a ​
unit cell for a H2MnO4 compound using vc-relax in ase-espresso. I have
got the following strange error:
"too many g-vectors"
I have used a e-cut of 45 Ry
​ which basically should be high enough​
.
​I have also tried with different e-cut values, both smaller and
bigger. For the former ones, I get the error of "*g*-*vectors
missing"*​
​. Although I am not sure,
I think this error has some thing to do with the e-cut.

During cell relaxation, it seems that the size of the cell changes
significantly by ~10 Angstrom^3.
​ Moreover, it seems that the I got this error in the last step just
before performing scf calculations on the optimized structure, where
the calculations fail.​

​ I have taken a cell_factor of 5,much larger than the default value,
i.e.,1.2. Below you can find the details of the calculators as well as
different parameters for vc-relax calculations. I would like to say
that I have used ase-espresso.

    calculator = espresso(pw=600,
        dw=6000,
        xc='PBE',
        kpts = (6,6,6),
        nbands=-10,
        mode='vc-relax',
        cell_dynamics='bfgs',
        opt_algorithm='bfgs',
        cell_factor=5,
        spinpol=spinpol,
        outdir= outdir)

Any help will be appreciated,

Best,

Reza
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