Theory of chemisorption and reactions on metal surfaces

Publisher Summary This chapter discusses several experimental studies conducted on cluster ions. Cluster ions comprise a nonrigid assembly of components having properties between those of large gas phase molecules and the bulk condensed state. Research on the properties of cluster ions is valuable in obtaining a complete understanding of the forces between ions and neutral atoms or molecules, where, for example, data on energetics provide a direct measure of the depth of the potential well of interaction between the ion and the collection of neutral molecules. There are three types of experimental approaches to produce and study these cluster ions depending on different degrees of physical isolation, that is, clusters moving freely in space (gas phase studies), clusters supported upon a substrate surface, and clusters existing in solids and liquids. Moreover, the use of cluster ions for fuel injection into fusion reactors and cluster ions are also present in other high-temperature systems such as those designed as sources of energy employing magnets and hydrodynamics.

Experimental studies on cluster ions

We have achieved stable Fourier transform limited single axial mode operation of an unstable resonator Nd:YAG oscillator by injection seeding of an external signal. A detailed theoretical and experimental treatment of axial mode selection via injection seeding is presented. Our study shows that the axial mode selection process in Q -switched lasers via injection seeding is quite different from the frequency locking in CW lasers via injection locking.

Single axial mode operation of a Q -switched Nd:YAG oscillator by injection seeding

The vibrational dynamics of formic acid dimer is quite regular at low fundamental excitation frequencies, whereas it evolves into a complex and irregular vibrational signature in the OH stretching region. This is evidenced by the first Raman investigation of the jet-cooled formic acid dimer and its three deuterated isotopomers. Subtle isotope effects in the inter-monomer stretching mode, which is directly observed for the first time at 194 cm−1, find an interpretation based on hydrogen bond weakening due to quantum delocalization of the protons. The reported high-frequency jet spectra should provide essential experimental stepping stones towards a more complete understanding of this planar prototype for strong double hydrogen bonding.

Raman jet spectroscopy of formic acid dimers: low frequency vibrational dynamics and beyond

Cars spectra of van der waals complexes: The structure of the CO2 dimer

Observation of saturation broadening of the coherent anti-stokes raman spectrum (cars) of acetylene in a pulsed molecular beam

Coherent anti-stokes raman scattering (cars) of large C2H4Ar clusters

The advantages of molecular beam coherent anti-stokes Raman spectroscopy include increased spectral resolution from sub-doppler linewidths, improved signal-to-noise resulting from spectral simplification due to rotational cooling upon expansion, and the possibility of studying molecular complexes generated by the expansion process. In this paper we report recent high resolution CARS studies using pulsed laser sources combined with a reliable pulsed molecular beam source and the first cw CARS measurements in a steady state high Mach number supersonic expansion.

F. König

Papers

Observation of saturation broadening of the coherent anti-stokes raman spectrum (cars) of acetylene in a pulsed molecular beam

Coherent anti-stokes raman scattering (cars) of large C2H4Ar clusters

Pulsed and CW Molecular Beam CARS Spectroscopy