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Re^4: Is there a Simple way to know HOMO-LUMO gap?

Siddheshwar Chopra

Dear Pasha,
I am REALLY thankful to you for making me understand this calculation. I have been stuck into it for a long time. I am really thankful Sir. Specially for your effort to make me understand in this wonderful and effective way.


On Tue Feb 5 '13 9:02am, Solntsev Pasha wrote
>I am not Alexei, but maybe attached picture will be useful.
>I made it from your attached file.

>On Tue Feb 5 '13 7:10am, Siddheshwar Chopra wrote
>>Dear Alexei,
>>I am actually running HESSIAN calculations. I looked for the string "EIGENVECTORS", and then nos. 149 and 150. But I still failed to get the HOMO-LUMO... I am atatching herewith a sample fiel for your reference. Please let me know the value of HOMO-LUMO from it..

>>On Mon Feb 4 '13 11:38pm, Alexei Popov wrote

>>>this can be done very simple.

>>>Run single point SCF energy calculation. Look at the output and you'll see strings like these:

>>> TOTAL NUMBER OF SHELLS              =   10
>>> NUMBER OF ELECTRONS                 =   12
>>> CHARGE OF MOLECULE                  =    0
>>> STATE MULTIPLICITY                  =    1

>>>Orbital #6 is HOMO and orbital #7 is LUMO.

>>>Look at the section

>>>          ------------
>>>          EIGENVECTORS
>>>          ------------

>>>and find the eigen-vectors #6 and #7 (they are numbered so it is easy)
>>>The numbers above the eigen-vectors are their energies. Substract two numbers for two orbitals and you'll get the answer.

>>>Alexei Popov
>>>On Mon Feb 4 '13 12:41pm, Siddheshwar Chopra wrote
>>>>Dear Sir,
>>>>Please forgive me for asking this question perhaps again in this forum. Actually I have completed the HESSIAN run and am able to read the HOMO,LUMO energies USING GABEDIT software. But I find it really too involving and error prone to calculate the HOMO-LUMO gap from the data. Please suggest em a simpler way so that I get the HOMO-LUMO gap directly...IS there any COMMAND I could add in the FIREFLY input file to get HOMO-LUMO printed in the output file directly?
>>>>If a command line input is not available, can Prof. Alex add ONE such command for the users?


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