Synchrotron radiation; VUV photoabsorption; Rydberg series; Ab initio calculations; Jahn-Teller effect; Vibrational analysis; PES reanalysis; CH3F
Abstract :
[en] The vacuum UV photoabsorption spectrum of CH3F has been recorded between 7 and 24 eV and has been analyzed in detail. Broad and structureless peaks are observed over the entire photon energy range. They are all assigned to transitions to Rydberg states, members of series converging to the 2e-1, 5a-1 and 1e-1 ionization limits. These features are underlying very long series of narrow and weak structures in the range of 10-13.2 eV. Through a continuum subtraction procedure, about 70 lines could clearly be identified. These have been assigned to long vibrational progressions belonging to Rydberg states corresponding to the 2e->3p and 2e->6s/5d configurations. These states are split by a Jahn-Teller distortion. Ab initio calculations lead to a Jahn-Teller stabilization energy of about 0.84 eV. The main features observed in the two bands are assigned to one single long vibrational progression of hcomega=0.160 eV (1290cm-1) related to the C-F Jahn-Teller inactive stretching vibration. The remaining structure is assigned to the low excitation of the Jahn-Teller active vibrational modes, i.e. the bending modes nu5 and nu6 characterized by hcomega5=0.120 eV (970 cm-1) and hcomega6=0.082 eV (660 cm-1). Leaning on the present results and assignments previously reported photoelectron spectroscopic data on CH3F+ [L. Karlsson, R. Jadrny, L. Mattsson, F.T. Chau, K. Siegbahn Phys.Scripta 16 (1977) 225] have been reconsidered and reinterpreted.
Research center :
Laboratoire de Dynamique Moléculaire
Disciplines :
Chemistry
Author, co-author :
Locht, Robert ; Université de Liège - ULiège > Département de Chimie (Faculté des sciences) > Laboratoire de Dynamique Moléculaire (Sciences)
Leyh, Bernard ; Université de Liège - ULiège > Département de chimie (sciences) > Laboratoire de dynamique moléculaire
Hoxha, A.
Dehareng, Dominique ; Université de Liège - ULiège > Centre d'ingénierie des protéines
Jochims, H.-W.; Freie Universität Berlin > Institut für Physikalische Chemie
Baumgärtel, H.; Freie Universität Berlin > Institut für Physikalische Chemie
Language :
English
Title :
About the Vacuum UV Photoabsorption Spectrum of Methyl Fluoride (CH3F): the fine structure and its vibrational analysis.
Alternative titles :
[fr] Du spectre de photoabsorption dans l'UV sous vide du Fluorure de Méthyle (CH3F): la structure fine et l'analyse vibrationnelle.
Tornow G., Locht R., Kaufel R., Baumgartel H., Jochims H.W. Chem. Phys. 1990, 146:305.
Locht R., Leyh B., Hottmann K., Baumgartel H. Chem. Phys. 1997, 220:207.
Locht R., Leyh B., Hottmann K., Baumgartel H. Chem. Phys. 1997, 220:217.
Hoxha A., Locht R., Leyh B., Dehareng D., Hottmann K., Baumgartel H. Chem. Phys. 2000, 256:239.
Momigny J., Locht R. Chem. Phys. Lett. 1993, 211:161.
Locht R., Momigny J., Ruhl E., Baumgartel H. Chem. Phys. 1987, 117:305.
Hoxha A., Locht R., Lorquet A.J., Lorquet J.C., Leyh B. J. Chem. Phys. 1999, 111:9259.
Weitzel K.M., Guthe F., Mahnert J., Locht R., Baumgartel H. Chem. Phys. 1995, 201:287.
Guthe F., Locht R., Leyh B., Baumgartel H., Weitzel K.M. J. Phys. Chem. A 1999, 103:8404.
Locht R., Momigny J., F. Lahmani (Ed.), Photophysics and Photochemistry above 6 eV, Elsevier, Amsterdam; 1985, 171.
Zhang W., Cooper G., Ibuki T., Brion C.E. Chem. Phys. 1989, 137:391.
Zhang W., Cooper G., Ibuki T., Brion C.E. Chem. Phys. 1991, 151:343.
Zhang W., Cooper G., Ibuki T., Brion C.E. Chem. Phys. 1991, 151:357.
Zhang W., Cooper G., Ibuki T., Brion C.E. Chem. Phys. 1991, 153:491.
Au J.W., Burton G.R., Brion C.E. Chem. Phys. 1997, 221:151.
Stokes S., Duncan A.B.F. J. Am. Chem. Soc. 1958, 80:6177.
Edwards L., Raymonda J.W. J. Am. Chem. Soc. 1969, 91:5937.
Sauvageau P., Gilbert R., Berlow P.P., Sandorfy C. J. Chem. Phys. 1973, 59:762.
Wu C.Y.R., Lee L.C., Judge D.L. J. Chem. Phys. 1979, 71:5221.
Olney T.N., Cooper G., Chan W.F., Burton G.R., Brion C.E., Tan K.H. Chem. Phys. 1994, 189:733.
Locht R., Leyh B., Denzer W., Hagenow G., Baumgartel H. Chem. Phys. 1991, 155:407.
Harshbarger W.R., Robin M.B., Lassettre E.N. J. Electr. Spectr. Related Phenom. 1973, 1:319.
Karlsson L., Jadrny R., Mattsson L., Chau F.T., Siegbahn K. Phys. Scripta 1977, 16:225.
Bieri G., Asbrink L., Von Niessen W. J. Electr. Spectr. Related Phenom. 1981, 23:281.
Gauld J.W., Radom L. J. Phys. Chem. 1994, 98:777.
Lugez C.L., Forney D., Jacox M.E., Ikura K.K. J. Chem. Phys. 1997, 106:489.
Herzberg G., Molecular Spectra and Molecular Structure. III. Electronic Spectra and Electronic Structure of Polyatomic Molecules, Van Nostrand, Princeton, NJ; 1967.
Frisch M.J., Trucks G.W., Schlegel H.B., Gill P.M.W., Johnson B.G., Robb M.A., Cheeseman J.R., Keith T.A., Petersson G.A., Montgomery J.A., Raghavachari K., Al-Laham M.A., Zakrzewski V.G., Ortiz J.V., Foresman J.B., Cioslowski J., Stefanov B.B., Nanayakkara A., Challocombe M., Peng C.Y., Ayala P.Y., Chen W., Wong M.W., Andres J.L., Replogle E.S., Gomperts R., Martin R.L., Fox D.J., Binkley J.S., Defrees D.J., Baker J., Stewart J.P., Head-Gordon M., Gonzalez C., Pople J.A., GAUSSIAN 94 (Revision D.4) Gaussian Inc., Pittsburgh, PA; 1996.
Moller C., Plesset M.S. Phys. Rev. 1934, 46:618.
Krishnan R., Pople J.A. Int. J. Quant. Chem. 1978, 14:91.
Hehre W.J., Ditchfield R., Pople J.A. J. Chem. Phys. 1972, 56:2257.
Clark T., Chandrasekhar J., Spitznagel G.W., Schleyer P.V.R. J. Comp. Chem. 1983, 4:294.
Scott A.P., Radom L. J. Phys. Chem. 1996, 100:16502.
Herzberg G., Molecular Spectra and Molecular Structure. II. Infrared and Raman Spectra of Polyatomic Molecules, Van Nostrand, New York; 1945.
Martin R.L., Davidson E.R. Mol. Phys. 1978, 35:1713.
Cohen E.R., Taylor B.N. J. Phys. Chem. Ref. Data 1973, 37:663.
