Firefly and PC GAMESS-related discussion club


 
Learn how to ask questions correctly  
 
 
We are NATO-free zone
 



Re: HOMO-LUMO GAP CALCULATION DOUBT....

Thomas
thomaspijper@hotmail.com


Dear Siddheshwar,

I'm not sure if I understand your question correctly. However, I would like to propose that you should calculate the HOMO-LUMO gap with:

Gap = LUMO - HOMO = 2.2 eV

which gives a positive number that looks normal to me.


Kind regards,
Thom



On Sat Apr 20 '13 9:34pm, Siddheshwar Chopra wrote
--------------------------------------------------
>Dear Sir,
>As learnt from the same forum about calculating HOMO-LUMO, I have got the final result as follows:

>Orbital No.     (in eV)
>161     LUMO     -2.25     A
>160     HOMO     -4.45     A

>Hence the GAP= HOMO-LUMO = -2.2 eV

>Now the doubt is that when I plotted the Density of states spectrum, I get to see a gap between the occupied and virtual orbitals (I have attached an image of it for your reference).. Please help me understanding this concept... Just now the calculations have shown a negative value, which in my opinion means overlapping occupied and virtual orbitals. Then how can a gap be seen? Am I going wrong in the calculations or something else. Please help..

>Regards,


[ Previous ] [ Next ] [ Index ]           Sun Apr 21 '13 3:01pm
[ Reply ] [ Edit ] [ Delete ]           This message read 895 times