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Re^8: Getting wrong result for TiO2 HOMO-LUMO gap...

Alex Granovsky
gran@classic.chem.msu.su

Dear Siddheshwar,

you should always use orbitals and orbital energies obtained at optimized geometry.

E(HOMO)=-0.2316    E(LUMO)= -0.1198
HOMO-LUMO gap = 0.1118 au = 3.04219 eV

Kind regards,
Alex Granovsky

On Fri May 30 '14 7:33am, Siddheshwar Chopra wrote
--------------------------------------------------
>Dear Alex,
>Please find attached the TiO2 o/p file for your reference. I used 1 Hartree=27.21 eV. Please let me know what wrong am I doing.

>Kind Regards,

>On Thu May 29 '14 3:12pm, Alex Granovsky wrote
>----------------------------------------------
>>Most likely, you are using wrong conversion factor from au to eV.

>>Kind regards,
>>Alex Granovsky
>>
>>
>>
>>On Thu May 29 '14 7:11am, Siddheshwar Chopra wrote
>>--------------------------------------------------
>>>Dear Alex,
>>>Yes you said right..HOMO orbital is 19th. But I am getting 0.68eV using 6-31G. Could you please help me?

>>>Kind Regards,

>>>On Wed May 28 '14 3:49pm, Alex Granovsky wrote
>>>----------------------------------------------
>>>>Hello,

>>>>with 6-31G, HOMO is orbital # 19

>>>>Kind regards,
>>>>Alex Granovsky
>>>>
>>>>
>>>>On Wed May 28 '14 8:24am, Siddheshwar Chopra wrote
>>>>--------------------------------------------------
>>>>>Dear Alex,
>>>>>A BIG Thanks for that explanation. The problem is solved..
>>>>>But could you try with 6-31G also. I got the same problem here too. Please have a look at that.

>>>>>Kind Regards,

>>>>>On Tue May 27 '14 3:28pm, Alex Granovsky wrote
>>>>>----------------------------------------------
>>>>>>The relevant lines of output are:

>>>>>> TOTAL NUMBER OF SHELLS              =   11
>>>>>> TOTAL NUMBER OF BASIS FUNCTIONS     =   50
>>>>>> NUMBER OF ELECTRONS                 =   38
>>>>>> CHARGE OF MOLECULE                  =    0
>>>>>> STATE MULTIPLICITY                  =    1
>>>>>>
>>>>>> NUMBER OF OCCUPIED ORBITALS (ALPHA) =   19
>>>>>> NUMBER OF OCCUPIED ORBITALS (BETA ) =   19
>>>>>>

>>>>>> TOTAL NUMBER OF ATOMS               =    3
>>>>>> THE NUCLEAR REPULSION ENERGY IS      124.9770929777

>>>>>>and

>>>>>>
>>>>>> THE ECP RUN REMOVES   14 CORE ELECTRONS, AND THE SAME NUMBER OF PROTONS.
>>>>>>

>>>>>> THE ADJUSTED NUCLEAR REPULSION ENERGY=       53.0405413922

>>>>>>So to get the HOMO # you should take 19 and then subtract 14/2

>>>>>>Kind regards,
>>>>>>Alex Granovsky
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>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