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Re^2: Getting wrong result for TiO2 HOMO-LUMO gap...

Siddheshwar Chopra
sidhusai@gmail.com

Dear Alex,
Thank you for resolving the problem. I have two questions:
1) Please explain how we get 12 and 13th orbital for HOMO, LUMO? I just understand that the total orbitals are 19 and hence 2 electrons per orbital. How do I decide the actual number of orbitals for HOMO/LUMO?
2) Also I got similar bandgap when 6-31G basis set was used. There are no core electrons removed here.

Kind Regards,

On Tue May 27 '14 12:34pm, Alex Granovsky wrote
-----------------------------------------------
>Hi,

>You should take into account that ECP removes core electrons.
>As a result, HOMO becomes orbital number 12, while LUMO is orbital
>number 13. The HOMO-LUMO gap is then ca. 3 eV.

>Kind regards,
>Alex Granovsky
>
>
>
>
>On Tue May 27 '14 10:16am, Siddheshwar Chopra wrote
>---------------------------------------------------
>>Dear Users,
>>Please see the following code I am using to run for a single TiO2 molecule. I have used SBKJC and also 6-31G to get almost similar results for HOMO-LUMO gap. I am getting around 0.7 eV. However as far as literature goes, I should have got ~ 3 eV. As it a sngle TiO2 molecule, gap should have opened.

>> $SYSTEM MEMORY=34459319 aoints=dist TIMLIM=5295600 KDIAG=-1 $END
>> $CONTRL INTTYP=HONDO ICUT=11 ITOL=30 RUNTYP=OPTIMIZE SCFTYP=RHF $END
>> $CONTRL DFTTYP=B3LYP COORD=UNIQUE NZVAR=3 $END
>> $CONTRL MAXIT=10000 MOLPLT=.t. PLTORB=.t. ECP=SBKJC $END
>> $BASIS GBASIS=SBKJC $END
>> $STATPT opttol=10E-7 NSTEP=200 Method=GDIIS HSSEND=.TRUE. $END
>> $SCF dirscf=.t. fdiff= .f. diis=.t. $END  
>> $DFT HFX(1)=0.15 LMAX=41 NRAD=99 $end
>> $ZMAT DLC=.t. AUTO=.t. $END
>> $SCF NCONV=7 $END
>> $DATA
>>TiO2
>>C1
>> TI         22.0  -2.7439906036  -2.7281069598  -0.4118294433
>> O           8.0  -3.1097257096  -4.1115914499   0.4209344416
>> O           8.0  -3.1706230814  -1.3977023214   0.4765961088
>> $END

>>Please refer the following reference for the same:

>> J. Mater. Chem. A,2014, 2,637

>>Please help,

>>Kind Regards,

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