Dear all
I
need some information on the molecular absolute hardness in my study, but I
don't know how to calculate it and which data I need to compute in
gaussion 09. Therefore, I need a detail computational process, formulas or
examples on gaining the molecular absolute hardness.
Any
help will be appreciated, I am looking forward to your timely
reply
Sincerely yours
As
defined by Pearson, absolute hardness is 1/2 the difference between the
ionization energy and electron affinity of a substance, with the energy of the
highest occupied molecular orbital being the negative of the ionization energy,
and the energy of the lowest unoccupied molecular orbital being the negative of
the electron affinity. So, the absolute hardness is half the difference
between the HOMO and LUMO orbitals, usually expressed in eV.
Hope
this helps,
Flick
_______________
William F.
Coleman
Professor of
Chemistry
Wellesley College
Wellesley MA
02481