Subject: I can't post my message

From: "sabry ahmed" <[email-masked]>
Date: Sun, 26 Jan 2003 10:43:56 +0300

Dear All,

I'm interested in computing the BDE(R-O2)for a series of halogenated peroxyl 
radicals at ab initio and DFT (B3LYP/6-31G** and B3LYP/6-311+G(2df,2p) 
levels.  For R=CH3, values of BDE(R-O2)=30.6 and 29.1 at  B3LYP/6-31G** and 
B3LYP/6-311+G(2df,2p), respectively, are published (J. Phys. Chem. A 1999, 
103, 7094).

I've tried to get these values by calculating the enthalpies of the 
following isogyric reaction:

CH3O2 + H2 = CH3O2H + H
CH3O2H + H2 = CH4 + H2O2

then, by combining these enthalpies with experimentally known heats of 
formation, the heat of formation of CH3O2 can be obtained. Finally, the 
enthalpy of the dissociation reaction: CH3O2 = CH3 + O2 , which is equal to 
the BDE(CH3O2)is calculated as follows:

  BDE(CH3O2)= heat of formation of CH3 - heat of formation of CH3O2

Unfortunately, I got BDE values of 44.4 and 37.1 kcal/mol instead of the 
published values 30.6 and 29.1 kcal/mol.  Is there something wrong in what 
I've done, or something I should do more?

thanks in advance, I'll summarize your responses.

yours,

-Sabry

current address:
Teachers College in Dammam
P.O. Box 2375
Dammam 31451
Kingdom of Saudi Arabia