Photodynamics of vibrationally state-selected nitrous oxide isotopomers

                                                          November 2001
PhD Position:
A 4-year PhD position, funded by the Dutch Physics Foundation FOM
(Fundamental Research of Matter, part of the Netherlands Organization
of Scientific Research NWO) within the program of Molecular Atmospheric
Processes, is available in the group of dr. Maurice H.M. Janssen at
the Laser Centre Vrije Universiteit in Amsterdam (
The position is available immediately. The FOM and the Free University
in Amsterdam offer a competitive salary, moving and other allowances.
The LCVU is a very internationally oriented research environment with
many foreign PhD students, Postdocs and visitors. The LCVU is recognized
by the European Union as a Large Scale Research Facility and a
Marie Curie Training Institute (see website).

In atmospheric science the analysis of stable isotopic species of
various molecules is used to monitor the budget and the (photo)chemical,
biological, geological and anthropomorphic processes in which these molecules
are involved. Nitrous oxide, N2O, is a prominent greenhouse gas and has
an important role in the catalytic depletion of ozone.
In the proposal presented here we want to explore and study our hypothesis
that in the wavelength region 200-210 nm (the stratospheric solar window)
photolysis of vibrationally excited nitrous oxide molecules (by far the dominant loss channel)
contributes significantly to the observed fractionation mechanism.
Towards the red part of this region it may even be the dominant channel for photolysis.
In our ion-imaging molecular beam machine we are able to prepare single-quantum
states of rovibrationally selected N2O (v_2=1, JlM), where the parent is
selected in the first excited level of the v_2 bending mode. We intend to
extend our first exploratory experiments on 14N14N16O to the other
isotopomers of nitrous oxide and will study in detail the state-to-state
unimolecular photofragmentation dynamics of vibrationally state-selected isotopomers.
Our collaboration with dr. G. Groenenboom (Institute of Theoretical Chemistry,
University of Nijmegen) and dr. M.S. Johnson (Department of Chemistry, University of Copenhagen)
will provide us with calculations on ab initio surfaces and provide theoretical insight
on the fractionation mechanism of isotopomers.

[1]     D.W. Neyer, A.J.R. Heck, D.W. Chandler, J.M. Teule and M.H.M. Janssen,
        J. Phys. Chem. 103 (1999), 10388-10397
[2]     J.M. Teule, G.C. Groenenboom, D.W. Neyer, D.W. Chandler and M.H.M. Janssen,
        Chem. Phys. Lett. 320 (2000), 177-185
[3]     M.S. Johnson, G.D. Billing, A. Gruodis and M.H.M. Janssen,
        J. Phys. Chem. A 105 (2001), 8672-8680

Contact and applications:
dr. Maurice H.M. Janssen
email:  [email protected]
phone:  +31(0)20-4447632
fax:    +31(0)20-4447643