Linker IT Software
menubar-top-links menubar-top-rechts
Home Help Search Login
Welcome, Guest. Please Login.
SQL*XL: Database to Excel bridge litLIB: Excel power functions pack ExcelLock: Locking and securing your valuable Excel spreadsheets encOffice: Protect your Excel file easy and safe encOffice: Protect your Excel file easy and safe
Pages: 1
HF band gap (Read 3478 times)
Gerrit-Jan Linker
YaBB Administrator

Posts: 75
HF band gap
23.03.11 at 06:53:21
HF band gap
To determine the band gap using HF theory one cannot just subtract the energy of the HOMO from the LUMO.  The HOMO is property optimised hower the LUMO is not. It is optimised 'looking inwards' to a neutral system wheras it should have been optimised against the positively charged ion.  
To calculate the band gap more properly at the HF level of theory the following formula can be used:
Eg,HF = E- + E+ - 2E0  
Eg,HF : The band gap at the HF level of theory
E- : The energy of the -1 charged system after relaxing orbitals
E+ : The energy of the ionised system after relaxing the orbitals
E0 : The energy of the neutral system
Actually the band gap should be reduced by Eexciton, the attraction energy between the hole and the excited electron of the exciton.
See also:
HF theory
Back to top
« Last Edit: 23.03.11 at 07:04:17 by Gerrit-Jan Linker »  

Gerrit-Jan Linker
Linker IT Software
Email WWW Gerrit-Jan Linker   IP Logged
Pages: 1