Dear fellow ADF-users,

Have you ever calculated total bond energies? If yes, please, read on and
tell me if you've ever encountered something like this:

Using the "fragment approach", I calculated total bond energies for some
uranyl chloride complexes, using uranyl and the different chlorides as
separate fragments. The following energies result:
(The correct charges were used. NOSYM was used in all cases.)

        
uo2cl: -15.16 eV
uo2cl2: -23.80 eV
uo2cl3: -27.42 eV
uo2cl4: -26.74 eV -> What is going on here?
uo2cl5: -21.16 eV -> And here???

How can it be that the total bond energy becomes smaller when you add more
ions??? More than 5.5 eV cannot be a numerical error, I guess?

The same result is found, of course, when I just calculate the total
bonding energy using the formula BE = E(complex) - E([UO2]2+) - n*E(Cl-).

Any comment is welcome!

Els
Received on 2005-03-18 15:26:57