Supersonic jet laser spectroscopy

The combination of supersonic-jet-laser spectroscopy and high-level ab initio calculations provides a powerful method for probing the geometrical structure and photophysical properties of small molecules. In this chapter, we described the experimental and theoretical characterizations of geometrical structures and elementary photoprocesses in supersonic free jet. The major focus of the review was on the OODR spectroscopy, which is designed to identify and characterize dark electronic states of the molecule. The main conclusions that emerge from the review can be summarized as follows. 

Supermolecule, 132, 231, 313. 341, 405 Supersonic Jet laser spectroscopy, 44, 367 Surface Jump. 217, 315-17, 483 Surface touching, 181-83, 217, 236, 3IS, 333. See also Crossing Symmetry selection rules. 30-32 Syn-anti isomerization, 374-75... 

Shimozono Y, Yamada K (2013) Ishiuchi, S.i., Tsukiyama, K, Fujii, M. Revised conformational assignments and conformational evolution of tyrosine by laser desorption supersonic jet laser spectroscopy. Phys. Chem. Chem. Phys. 15(14) 5163-5175... 

A number of less commonly used analytical techniques are available for determining PAHs. These include synchronous luminescence spectroscopy (SLS), resonant (R)/nonresonant (NR)-synchronous scan luminescence (SSL) spectrometry, room temperature phosphorescence (RTP), ultraviolet-resonance Raman spectroscopy (UV-RRS), x-ray excited optical luminescence spectroscopy (XEOL), laser-induced molecular fluorescence (LIMP), supersonic jet/laser induced fluorescence (SSJ/LIF), low- temperature fluorescence spectroscopy (LTFS), high-resolution low-temperature spectrofluorometry, low-temperature molecular luminescence spectrometry (LT-MLS), and supersonic jet spectroscopy/capillary supercritical fluid chromatography (SJS/SFC) Asher 1984 Garrigues and Ewald 1987 Goates et al. 1989 Jones et al. 1988 Lai et al. 1990 Lamotte et al. 1985 Lin et al. 1991 Popl et al. 1975 Richardson and Ando 1977 Saber et al. 1991 Vo-Dinh et al. 1984 Vo- Dinh and Abbott 1984 Vo-Dinh 1981 Woo et al. 1980). More recent methods for the determination of PAHs in environmental samples include GC-MS with stable isotope dilution calibration (Bushby et al. 1993), capillary electrophoresis with UV-laser excited fluorescence detection (Nie et al. 1993), and laser desorption laser photoionization time-of-flight mass spectrometry of direct determination of PAH in solid waste matrices (Dale et al. 1993). 

Although there were some early attempts to analyze the vibrational fine structure contained in the near ultraviolet vapor phase spectrum of acetaldehyde, these studies were generally unsuccessful because of the diffuse and congested nature of the bands. It has only been in the last several years that the problem has been resolved by the powerful techniques of supersonic jet-laser excitation spectroscopy. 

Nesbitt D J 1994 High-resolution direct infrared laser absorption spectroscopy in slit supersonic jets intermolecular forces and unimolecular vibrational dynamics in clusters Ann. Rev. Phys. Chem. 45 367-99... 

Laser spectroscopy is such a wide subject, with many ingenious experiments using one or two CW or pulsed lasers to study atomic or molecular stmcture or dynamics, that it is difficult to do justice to it at the level at which Modern Spectroscopy is aimed. In this edition 1 have expanded the section on supersonic jet spectroscopy, which is an extremely important and wide-ranging field. 

This chapter deals mainly with (multi)hyphenated techniques comprising wet sample preparation steps (e.g. SFE, SPE) and/or separation techniques (GC, SFC, HPLC, SEC, TLC, CE). Other hyphenated techniques involve thermal-spectroscopic and gas or heat extraction methods (TG, TD, HS, Py, LD, etc.). Also, spectroscopic couplings (e.g. LIBS-LIF) are of interest. Hyphenation of UV spectroscopy and mass spectrometry forms the family of laser mass-spectrometric (LAMS) methods, such as REMPI-ToFMS and MALDI-ToFMS. In REMPI-ToFMS the connecting element between UV spectroscopy and mass spectrometry is laser-induced REMPI ionisation. An intermediate state of the molecule of interest is selectively excited by absorption of a laser photon (the wavelength of a tuneable laser is set in resonance with the transition). The excited molecules are subsequently ionised by absorption of an additional laser photon. Therefore the ionisation selectivity is introduced by the resonance absorption of the first photon, i.e. by UV spectroscopy. However, conventional UV spectra of polyatomic molecules exhibit relatively broad and continuous spectral features, allowing only a medium selectivity. Supersonic jet cooling of the sample molecules (to 5-50 K) reduces the line width of their... 

Ito M., Ebata T. and Mikami N. (1988) Laser Spectroscopy of Large Polyatomic Molecules in Supersonic Jets, Ann. Rev. Phys. Chem. 

Since the turn of the present century, a series of linear complexes with the general formula NgMX (Ng = Ar, Kr, Xe M = Cu, Ag, Au X = F, Cl, Br) have been prepared and characterized by physical methods. These complexes were prepared by laser ablation of the metal from its solid and letting the resulting plasma react with the appropriate precursor. The complexes formed were then stabilized in a supersonic jet of argon gas. Characterization of these complexes was carried out mainly by microwave spectroscopy. 

Two-colour photoionization spectroscopy of aniline cooled in a supersonic jet. Strong propensity for vertical (An = 0) ionization allows vibrational frequencies of CgHgNH2 ( B,) to be determined Two-colour photoacoustic and MPI spectra of aniline, determined as a function of time delay between the two laser pulses. Observed both ionization and dissociation t MPI/TOF mass spectrometric study of phenol. Mechanism of ionization and ion fragmentation t MPI/TOF mass spectrometric study of fragmentation patterns in benzaldehyde. Strong wavelength dependence observed at 266 and 355 nm. Results show operation of two different mechanisms at these excitation wavelengths... 

Most investigations of photoinduced electron transfer have been performed in condensed phases. Much less is known about conditions that permit the occurrence of intramolecular ET in isolated (collision-free) molecular D-A systems. A powerful method for this kind of study is the supersonic jet expansion teehnique (which was originally developed by Kantrowitz and Grey in 1951 [66]) combined with laser-induced fluorescence (LIF) spectroscopy and time-of-flight mass spectrometry (TOF-MS). On the other hand, the molecular aspects of solvation can be studied by investigations of isolated gas-phase solute-solvent clusters which are formed in a supersonic jet expansion [67] (jet cooling under controlled expansion conditions [68] permits a stepwise growth of size-selected solvation clusters [69-71]). The formation of van der Waals complexes between polyatomic molecules in a supersonic jet pro-... 

Figure 2. Characterization of intermolecular exci-plexes by hole-burning spectroscopy. Adapted from Ref. [22a] (a) Fluorescence excitation ( emission set at 375 nm) and (b) hole-burning spectra of the R-isomer of the anthracene-dimethylaniline (An-DMA) adduct in a supersonic jet. The probe laser was tuned on the most intense line of the adduct. Lines marked with asterisks are due to bare anthracene, (c) Fluorescence excitation ( emission set at 450 nm) and (d) hole-burning spectra of the E-isomer of the An- DMA adduct in a supersonic jet. The probe laser was tuned to the maximum of the broad exciplex excitation band.

Laser-induced multiphoton ionization spectroscopy has been applied to the parent, methyl-, and chloro-substituted pyrazines <85ANC29ll). The ions produced by laser photoionization in the supersonic jet are mass-analyzed using a time of flight mass spectrometer, in which the spectra obtained reflect the absorption of the n-n transition. Mass-resolved excitation spectroscopy by laser ionization in the infrared region has also been applied to the conformational analysis of a-alkyl substituted pyrazines <92JA5269). Dynamic and structural properties of electronically excited states of pyrazine have been elucidated from high resolution laser spectroscopy with MHz resolution <88JST(173)201). 

Lovejoy C M, Schuder M D and Nesbitt D J 1986 High resolution IR laser spectroscopy of Van der Waals complexes in slit supersonic jets observation and analysis of v,, v, + and + 2v in ArHF J. Chem. Phys. 85 4890-902... 

Ray D, Robinson R L, Gwo D H and Saykally R H 1986 Vibrational spectroscopy of Van der Waals bonds measurement of the perpendicular bend of ArHCI by intracavity far infrared laser spectroscopy of a supersonic jet J. Chem. Phys. 84 1171-80... 

Busarow K L, Blake G A, Laughlin K B, Cohen R C, Lee YT and Saykally R J 1987 Tunable far-infrared laser spectroscopy in a planar supersonic jet the Z bending vibration of Ar-H CI Chem. Phys. Lett. 141 289-91... 

Li, L. and Lubman, D., "Pulsed Laser Desorption Method for Volatilizing Thermally Labile Molecules for Supersonic Jet Spectroscopy," Rev. Sci Instrum. 59, 557-561, 1988. 

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