PHD POSITION
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Dynamics of molecule formation on interstellar ices: thermal or UV-induced?
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Applications (deadline July 31 2007) are invited for a PhD position
for theoretical research on the dynamics of chemical reactions on ice
surfaces at the Leiden Institute of Chemistry and Leiden Observatory
of Leiden University, The Netherlands. The research will be carried
out in the framework of a collaboration between the Theoretical
Chemistry group (Prof. G.J. Kroes, Dr. R.A. Olson) and the
Astrochemistry group (Prof. E.F. van Dishoeck), with funding from the
Netherlands Organization for Scientific Research NWO on a TOP-project
"The role of excited electronic and vibrational states in chemical
reactions on surfaces". A description of the research is given below.
Applications should include a curriculum vitae (with a list of grades
for university exams), a brief statement of research experience, and
the names of at least two people who can serve as a
reference. Selection of candidates will start on July 31 2007 and will
continue until the position is filled. The position is open to
students of all nationalities with a degree in chemistry, physics or
astronomy. The starting date for the position is flexible up to
January 1 2008. Please send applications to:
Prof. dr. E.F. van Dishoeck
Leiden Observatory
P.O. Box 9513
2300 RA Leiden
The Netherlands
FAX: +31-71-5275819
e-mail: [log in to unmask]
See http://www.theorchem.leidenuniv.nl/
http://www.strw.leidenuniv.nl/~ewine/
Project description
====================
In dense interstellar clouds where new stars and planets are formed,
small dust particles (consisting of ~0.1 micron silicates) are covered
by ice mantles consisting of H2O, CO, CO2, CH4 and other species, at a
temperature of about 10 K. Recent observations show that larger
molecules such as H2CO, CH3OH, and HCOOH may be present as well.
These molecules can either form by thermal hydrogenation and oxidation
reactions of smaller molecules such as CO, or by photon-induced
processes.
In the PhD project, the above mentioned reactions are studied by
performing molecular dynamics simulations to "make" particles of
amorphous ice in the computer. Next, the reaction of CO with H on the
surface of such particles will be modelled using quantum transition
state theory. In addition, classical trajectory calculations will be
performed to obtain mechanistic insights into the most important
pathways, and to visualize these reactions. Subsequently, the effects
of UV photons, which can dissociate the H2O ice to form energetic OH
and H, will be considered. Reactions of energetic OH with CO is
thought to be a principle route to form CO2. The central goal of the
project is to determine which chemical reactions can occur on
interstellar ices, and to determine the dominant reaction mechanisms:
thermal or UV. If time permits, photodesorption processes of simple
ices will be modelled as well. Complementary laboratory experiments
on these reactions are being carried at the Sackler Laboratory at
Leiden Observatory.
Term of appointment: 4 yr
Required: Degree in Chemistry, Physics, or Astronomy, with an interest
in molecular dynamics. Experience with numerical methods and computer
programming will be helpful.
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