Martin Vala
Professor of Chemistry

Department of Chemistry
University of Florida

VOICE: (352) 392-0529

EMAIL: mvala@chem.ufl.edu

HOMEPAGE: http://www.chem.ufl.edu/vala.html

Research Interests

The main thrust of our work is on the preparation and spectroscopic study of unstable species that may contribute to signals observed from interstellar space. Most of these species are carbon-containing radicals and/or ions produced by laser ablation electron-bombardment or plasma glow discharge. The species are trapped in low temperature rare gas matrices and investigated by Fourier transform infrared or Raman spectroscopy and visible/ultraviolet absorption or emission spectroscopy. We are presently developing a cavity ring-down spectrometer with an effective path length of over sixty meters for use on cold unstable gas phase species.

We have been actively involved in studies on polycyclic aromatic hydrocarbon cations and carbon chain anions as possible carriers of the so-called "unidentified infrared (UIR)" emission bands, a set of bands observed from outer space. The origin of these bands is still not fully understood, even though their existence was discovered over twenty-five years ago.

Recent Publications

J. Szczepanski, S. Ekern, and M. Vala, "Vibrational Spectroscopy of Small Matrix-Isolated Linear Carbon Cluster Anions", J. Phys. Chem. 101, 1841(1997).
Small carbon cluster anions (C3-, C5-, C6-, C7-, and C9-) were studied via matrix isolation infrared spectroscopy and theoretical calculations.

J. Szczepanski, C. Wehlburg and M. Vala, "C3- Carbon Cluster Anion: Structure and Asymmetric Stretching Mode Frequency", J. Phys. Chem., 101, 7039 (1997).

An isotopic (12C / 13C) infrared study of the title anion confirmed its linear shape and infrared CC stretching frequency.

J. Szczepanski, E. Auerbach and M. Vala, "C6- Carbon Cluster Anion: An Infrared Absorption and Resonance Raman Isotopic Study", J. Phys. Chem., 101, 9296(1997).

Resonance Raman and infrared spectroscopy has been used to characterize the C6- anion as a linear species in argon matrices.

S. Ekern, A. G. Marshall, J. Szczepanski, and M. Vala, "Photon-Induced Complete Dehydrogenation of Putative Interstellar Polycyclic Aromatic Hydrocarbon Cations: Coronene and Naphtho-[2,3-a]Pyrene", Astrophys. J., 488, L39(1997).

Irradiation from a simple xenon lamp can strip the hydrogens from the title compounds trapped in an ion cyclotron resonance spectrometer.

S. Ekern, A. G. Marshall, J. Szczepanski, and M. Vala, "Photodissociation of Gas-Phase Polycyclic Aromatic Hydrocarbon Cations", J. Phys. Chem., 102, 3498 (1998)

The visible irradiation of PAH cations in an ion cyclotron resonance spectrometer can lead to a variety of products.

J.Szczepanski, R.Hodyss and M.Vala, "Isotopic Infrared Absorption Study of C5- , C7- and C9 Carbon Cluster Anions in Argon Matrices", J.Phys. Chem. 102, 8300 (1998)

The title cluster anions were produced by a novel dual laser beam technique, trapped in argon matrices and studied via infrared Fourier transform spectroscopy

L.Lapinski and M.Vala, "Linear C11 Cluster: An Isotopic Infrared Study", Chem. Phys. Letts. 300, 195 (1999)

The major infrared vibrational frequencies of the linear C11 cluster in argon and nitrogen matrices are detailed.

J.Szczepanski, R.Hodyss, J.Fuller and M.Vala, "Infrared Absorption Spectroscopy of Small Carbon-Sulfur Clusters Isolated in Solid Argon", J. Phys. Chem. 103, 2975 (1999) Possible interstellar molecules of the form CnS and CnS2 were characterized via infrared spectroscopy.