Subject: NEGATIVE ACTIVATION E's

From: "E. Lewars" <[email-masked]>
Date: Mon, 3 Aug 1998 13:32:52 -0400 (EDT)

Monday 1998 August 3

Hello,

Sometimes one gets a _negative_ value for an activation E.  For example

                  O               O
                   \\              \\...
                    C---O           C---O
                    |   |  ----->   .   . transition state   --> CO2 + N2
                    N===N           .   .
                                    .....
                                    N====N
                -297.56194 h
                                     -297.56281 h

      activ E = -0.00087 h = -2.28 kJ/mol     G2(MP2) energies

 Sometimes one gets a negative value with and without the ZPE corection.

 Is there any special theoretical significance to such "impossible"
activation E's?  Or can one just say that (since not much below zero) they
are compatible with a low positive barrier?

     Thanks

              E. Lewars
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