Abstract
Laser desorption followed by jet-cooling allows wavelength-selective as well as mass-selective detection of molecules desorbed from a surface without fragmentation. The cooling characteristics and detection sensitivity of laser desorption jet-cooling of organic molecules are investigated. From the rotational contour of the electronic origin of the S 1 ← S 0 transition of laser-desorbed anthracene, rotational cooling to 5–10 K is demonstrated. Vibrational cooling is studied for laser-desorbed diphenylamine, a molecule with low-energy vibrations, and a vibrational temperature below 15 K is found. The absolute detection sensitivity is determined for the perylene molecule. Using two-color (1+1) resonance enhanced multi-photon ionization (with a measured ionization efficiency of 0.25) for detection, it is found that one ion is produced in the detection region for every 2×105 perylene molecules evaporated from the desorption laser spot. A two-color (1+1) REMPI spectrum (400 points) of perylene is recorded using only 30 picogram of material.
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References
J.R. Cable, M.J. Tubergen, D.H. Levy: J. Am. Chem. Soc. 109, 6198 (1987)
Liang Li, David M. Lubman: Rev. Sci. Instrum. 59, 557 (1988)
J.R. Cable, M.J. Tubergen, D.H. Levy: J. Am. Chem. Soc. 110, 7349 (1988)
Lasers in Mass Spectrometry, ed. by D. Lubman (Oxford University Press, Oxford 1990)
G. Meijer, M.S. de Vries, H.E. Hunziker, H.R. Wendt: J. Chem. Phys. 92, 7625 (1990)
G. Meijer, M.S. de Vries, H.E. Hunziker, H.R. Wendt: J. Phys. Chem. 94, 4394 (1990)
D.H. Levy: Science 214, 263 (1981)
V.S. Letokhov: Laser Photo-ionization Spectroscopy (Academic, New York 1987)
P. Arrowsmith, M.S. de Vries, H.E. Hunziker, H.R. Wendt: Appl. Phys. B 46, 165 (1988)
Y. Kamura, K. Seki, H. Inokuchi: Chem. Phys. Lett. 30, 35 (1975)
W.C. Wiley, I.H. McLaren: Rev. Sci. Instrum. 26, 1150 (1955)
J.S. Baskin, A.H. Zewail: J. Phys. Chem. 93, 5701 (1989)
T.R. Hays, W. Henke, H.L. Selzle, E.W. Schlag: Chem. Phys. Lett. 77, 19 (1981)
J.W. Hager, S.C. Wallace: Anal. Chem. 60, 5 (1988)
A. Amirav, C. Horwitz, J. Jortner: J. Chem. Phys. 88, 3092 (1988)
B.W. Keelan, A.H. Zewail: J. Chem. Phys. 82, 3011 (1985)
W.R. Lambert, P.M. Felker, J.A. Syage, A.H. Zewail: J. Chem. Phys. 81, 2195 (1984)
G. Meijer, M.S. de Vries, H.R. Wendt, H.E. Hunziker: To be published
A.J. Kaziska, S.A. Wittmeyer, A.L. Motyka, M.R. Topp: Chem. Phys. Lett. 154, 199 (1989)
E. Clar, W. Schmidt: Tetrahedron 33, 2093 (1977)
S. Leutwyler: J. Chem. Phys. 81, 5480 (1984)