QUANTUM ESPRESSO常见报错以及解决方法
(1）Too many bands are not converged
错误内容如下：
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%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
Error in routine c_bands (1):
too many bands are not converged
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
stopping ...
相应的报错内容在QE/PW/src/c_bands.f90
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IF ( notconv > MAX( 5, nbnd / 4 ) ) THEN
!
CALL errore( 'c_bands', 'too many bands are not converged', 1 )
!
ELSEIF ( notconv > 0 ) THEN
!
WRITE( stdout, '(5X,"c_bands: ",I2, " eigenvalues not converged")' ) notconv
!
ENDIF
出现该报错的原因是notconv太大导致。 可以通过1.increase ecutwfc; 2.decrease conv_thr; or both do them来解决。
（2） SCF correction compared to forces is large: reduce conv_thr to get better values
出现该内容在输出文件中的内容：
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Total force = 0.000018 Total SCF correction = 0.000015
SCF correction compared to forces is large: reduce conv_thr to get better values
在代码中的内容：
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!
sumfor = SQRT( sumfor )
sumscf = SQRT( sumscf )
!
WRITE( stdout, '(/5x,"Total force = ",F12.6,5X, &
& "Total SCF correction = ",F12.6)') sumfor, sumscf
!
IF ( ( sumfor < 10.D0*sumscf ) .AND. ( sumfor > nat*eps ) ) &
WRITE( stdout,'(5x,"SCF correction compared to forces is large: ", &
& "reduce conv_thr to get better values")')
