|Joe Scanlon (Scanlonj)
Post Number: 10
|Posted on Wednesday, February 10, 2010 - 6:03 pm: |
Very nice poster. I have a couple of questions. First, is there evidence that NO reacting with the Crigee Intermediate is a major source of NO2? Second, do you see a big difference in the relative energies of the reaction mechanism when adding a ZPE correction? Good work dealing with such a complicated reaction!
|Lindsey Madison (Madisonl)
Post Number: 14
|Posted on Wednesday, February 10, 2010 - 8:57 pm: |
Great poster Cheryl!
I am hoping you can give me a few more comments on Figure 1 where you have redrawn Presto and Donahue's reaction pathway and included your own calculations. In particular, is your TS IX-A and TS IX-B related to Presto's and Donahue TS IX? If so, what accounts for such a large difference in energy?
|Cheryl Zogg (Caz)
Post Number: 2
|Posted on Wednesday, February 10, 2010 - 11:20 pm: |
1) The reaction was chosen more for the prevalence of the nitrogen species in the atmosphere than for any particular empirical evidence of the reaction. It simply has not been studied enough to know one way or the other.
2) As a matter of practice, the energies were adjusted to account for zero point energies. While I do not have my results in front of me, I would say that the correction had a noticeable effect generally on the order of half a hartree or less (with some variation across the different species).
|Cheryl Zogg (Caz)
Post Number: 3
|Posted on Wednesday, February 10, 2010 - 11:29 pm: |
Unfortunately, I have no way of knowing what the actual structure of Presto and Donahue's TS IX was. All their original paper provides is the relative energy. When I scanned for the structure using their model chemistry, my jobs kept centering on two distinct structures that became TS IX-A and TS IX-B. In every other case, I did manage to find something consistent with their work, but that one completed eluded me. What resulted was our reinterpretation of the progression as a two-step mechanism.
One of my biggest challenges arising from their work was that they are not a team of computational chemists. The work they did was only to prove a theoretical aspect of radical scavenging. As such, the original mechanism became more of a guide than a previous authority.
Hope that helps to answer your question.