Jet spectroscopy

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. 

If two different three-dimensional arrangements in space of the atoms in a molecule are interconvertible merely by free rotation about bonds, they are called conformationsIf they are not interconvertible, they are called configurations Configurations represent isomers that can be separated, as previously discussed in this chapter. Conformations represent conformers, which are rapidly interconvertible and are thus nonseparable. The terms conformational isomer and rotamer are sometimes used instead of conformer . A number of methods have been used to determine conformations. These include X-ray and electron diffraction, IR, Raman, UV, NMR, and microwave spectra, photoelectron spectroscopy, supersonic molecular jet spectroscopy, and optical rotatory dispersion (ORD) and CD measurements. Some of these methods are useful only for solids. It must be kept in mind that the conformation of a molecule in the solid state is not necessarily the same as in solution. Conformations can be calculated by a method called molecular mechanics (p. 178). 

C. Cezard, C. A. Rice, and M. A. Suhm, OH stretching redshifts in bulky hydrogen bonded alcohols Jet spectroscopy and modeling. J. Phys. Chem. A 110, 9839 9848 (2006). 

P. Zielke and M. A. Suhm, Raman jet spectroscopy of formic acid dimers Low frequency vibrational dynamics and beyond. Phys. Chem. Chem. Phys. 9, 4528 4534 (2007). 

C. Duan and D. Luckhaus, High resolution IR diode laser jet spectroscopy of malonaldehyde. Chem. Phys. Lett. 391, 129 133 (2004). 

Ultrafast Dynamics of IVR in Molecules and Reactions, P. M. Felker and A. H. Zewail, in Jet Spectroscopy and Molecular Dynamics, M. Hollas and D. Phillips, Eds., Chapman Hall, Blackie Academic, Oxford, 1995, p. 222. 

Fig. 4. An ortho-methyl group in diethylamino-pyrimidin induces some ground state twist and hence energetically destabilizes the B state but not yet sufficiently to make the population of the A state a najor process in supersonic jet spectroscopy. Upper panel dispersed fluorescence spectra of the jet-cooled bare molecule [36]. In clusters with methanol, the TICT state is preferentially lowered, and the majority of the ob rved red-shifted fluorescence can be assign l to arise from the TICT state (lower panel). This does not occur for the compound without an ortho-methyl group.

Commentary on Picosecond jet spectroscopy and photochemistry Energy redistribution and its impact on coherence, isomerisation, dissociation and solvation,... 

Years of Physical Chemistry PICOSECOND-JET SPECTROSCOPY AND PHOTOCHEMISTRY... 

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