simple rate question

[quietrain]

if i have oxygen + photons => products

if this is an elementary process, is this a uni-molecular process or a bi-molecular process?

i.e do we count photons as a molecule?

thanks!

[Borek]

do we count photons as a molecule?

We don't.

[quietrain]

thanks!

[juanrga]

if i have oxygen + photons => products

if this is an elementary process, is this a uni-molecular process or a bi-molecular process?

i.e do we count photons as a molecule?

thanks!

It is bi-molecular because without photons there is not reaction

Photons are treated as any other reactant. The rate for your process is

V = k [ oxigen ] [ photons ]

Under certain conditions this second order looks as pseudo-first order or as pseudo-zero-order.

For example if photons are in excess then its concentration is approximately constant and the rate can be approximated by the pseudo-first-order

V = k' [ oxigen ]

with k' = k [ photons ]

See http://pubs.acs.org/doi/pdf/10.1021/ed082p37.3 and references therein for a more detailed discussion and examples.