[Pw_forum] about band gap

[Ezad Shojaee]

Hi everyone
i am trying to obtain the band gap of TiO2(Anatase) and i did not have 
better than about 9ev ( instead of  3.2 ! )  i have tried many paths in the 
BZ including high-symmetry points & also i tried { automatic } k_points  but 
it did not help.
any suggestion will be appreciated
this in my input file for band structure

&control
    calculation='nscf'
    prefix='TiO2',
    pseudo_dir = '/root/pseudo/',
    outdir='/root/tmp/'
/
&system
    ibrav= 7,  celldm(1) =7.155,   celldm(3) =2.5136,
    nat=  6, ntyp= 2,
    ecutwfc =50.0,
    nbnd = 30,
/
&electrons
/
ATOMIC_SPECIES
Ti  47.867     Ti.vdb.UPF
O   15.9994    O.vdb.UPF
ATOMIC_POSITIONS
Ti  0.12500000 -0.12500000 -0.25000000
Ti -0.12500000  0.12500000  0.25000000
O   0.08159975  0.33159975 -0.16319950
O  -0.08159975 -0.33159975  0.16319950
O   0.33159975  0.08159975  0.33680050
O  -0.33159975 -0.08159975 -0.33680050
K_POINTS { automatic }
9  9  9   0 0 0

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