Subject: Photoionization experiments

From: Alberto LUNA <[email-masked]>
Date: Tue, 17 Nov 1998 11:13:13 +0100 (NFT)

Dear colleagues, 

  I have some ab initio results and I would like to compare them with 
photoionization mass spectrometry experiments. These experiments 
report the threshold energies observed for various photidisociative 
ionization reactions and identify them with the appearance potentials 
of fragments. My results agree remarkably with these data despite of 
the fact that they also predict high barriers in the disociation path.
My questions are:

  When experimentalists measure threshold energies, are they measuring 
appearance potentials or are they measuring in some way the barrier (if 
any)?

   Are they able to estimate appearance potentials from threshold 
measurements in spite of the presence of barriers in the reaction path?

Thank you to everybody

Alberto Luna
Universite Pierre et Marie Curie-Paris VI
4 Place Jussieu, Paris

e-mail: [email-masked]