Re: [Wien] How to get accurate GAP using BJ or mBJ methods?

2016-03-04 Thread tran
Hi, As David said, (a,b,c) were fitted to reproduce at best the experimental band gap of 23 solids. mBJ works quite well for many other solids not included in this set, but there are also (many) cases where the mBJ band gap is relatively far from experiment (still too small, but better than

[Wien] Crystal structure that XCrySDen cannot visualize

2016-03-04 Thread delamora
Dear WIEN2k community, There is a strange thing with a crystal structure, I am playing with Gd and H2O, so I put the following structure (I erased some lines); P LATTICE,NONEQUIV.ATOMS: 4 1_P1 MODE OF CALC=RELA unit=ang

Re: [Wien] How to get accurate GAP using BJ or mBJ methods?

2016-03-04 Thread Parker, David S.
Pablo, if you read Fabien's original 2009 PRL on the mBJ the parameters (a.b.c) were chosen to reproduce Experimental band gaps. This does not call the work into question, the basic method is on solid ground, but there is a certain empirical fitting involved. It usually does reasonably well

Re: [Wien] How to get accurate GAP using BJ or mBJ methods?

2016-03-04 Thread delamora
Dear Fabien, I think that there is a confusion here; Semi empirical methods need parameters and one get, adjusting parameters, good results On the other hand DFT, in principle, does not need adjustable parameters. There are issues that need adjustable parameters,

Re: [Wien] (no subject)

2016-03-04 Thread Muhammad Sajjad
here is optimized SnO2 structure blebleble P LATTICE,NONEQUIV.ATOMS: 2 136_P42/mnm MODE OF CALC=RELA unit=bohr 8.990462 8.990462 6.039906 90.00 90.00 90.00 ATOM -1: X=0. Y=0. Z=0. MULT= 2 ISPLIT= 8 -1: X=0.5000 Y=0.5000

Re: [Wien] (no subject)

2016-03-04 Thread mourad boujnah
Dear Qassim The problem is in RMT of your structure so in the initialisation use 5% to reduce it then it will works. Good luck. On Mar 4, 2016 10:23 AM, "Qasim Mahmood" wrote: > Dear Wien2k users I want to optimize the the tetragonal structure of SnO2 > with space group

[Wien] (no subject)

2016-03-04 Thread Qasim Mahmood
Dear Wien2k users I want to optimize the the tetragonal structure of SnO2 with space group 136_P42/mnm, the error of OPT_vol_-5.0 Stop error will occure at the start, please help me, What should i do to overcome this error Thanks and and regards qasim *Mr.Qasim Mahmood* *Ph.D