[Pw_forum] The band gap problem

[#TAO JUNGUANG#]

Hi Dear pwscf user

 I am simulating the band structure of TiO2, at first ,I use nscf to
calculate the band structure of TiO2 ,and got the band gap of 3.3eV
,which is very close to the experiment value. But as the following, I
use the input file like this to calculate the DOS,
&inputpp
   outdir='/home/tao/NEW_TiO2/band/new/test/'
    prefix='TiO2'
    fildos='TiO2.dos'
    Emin=3.0, Emax=25.0, DeltaE=0.1
   
/
     And my dos figure show that the band gap is about 2eV. So I am
confused , I think these two method should give me the same value of the
band gap, but they are different. So is there anyone who can tell me
why? Thanks in advance.