Laser photofragmentation

Lee Y-Y, Leone S R, Champkin P, Kaltoyannis N and Price S D 1997 Laser photofragmentation and coiiision-induced reactions of sit and siH - Chem. Phys. 106 7981-94... 

R. C. Sausa, V. Swayambunathan and G. Singh, Detection of Energetic Materials by Laser Photofragmentation/Fragment Detection and Pyrolysis/Laser-Induced Fluorescence, ARL-TR-2387, U.S. Army Research Laboratory (2001). 

In a series of XeCl excimer laser photofragmentation and reaction tests with O2 and ammonia reactants, we were able to prove that all these clusters were, in fact, (Lax C,) lanthanum fuUerenes. As levitated positive ions in the FT-ICR apparatus, they are chemically inert, and they fragment only by successive C2 loss. Laser shrink wrapping experiments showed that the smallest cage that can surround two lanthanum atoms is and the minimum cage that can fit around three is Cgg. 

II. Laser photofragmentation time-of-flight mass spectrometry, 5 A. Rotating beam source photofragmentation apparatus, 6... 

LASER PHOTOFRAGMENTATION TIME-0F-FLIGHT MASS SPECTROMETRY 5... 

II. LASER PHOTOFRAGMENTATION TIME-OF-FLIGHT MASS SPECTROMETRY... 

Because of the rapid dissociation of vibrationally excited HS radicals in the state, the determination of the HS(Z) vibrational distribution has not been made by the LIF method [128], Previous laser photofragmentation TOF mass spectrometric [129,131,132] and Doppler spectroscopic [130] experiments indicate that HS(X) formed by process 42 is vibrationally excited, up to v = 6, with the HS vibrational distribution peaked strongly at V = 0. Recently, Continetti et al. [132] have observed the 193-nm photodissociation of HS(X, v) (process 43) formed in process 42 at high photodissociation laser powers ... 

The first direct examination of primary photoproducts of thiophene at 193 nm has been made in a recent laser photofragmentation TOF mass spectrometric experiment [175], In this experiment, six product channels were identified, as summarized by processes 70-75 in decreasing order of importance ... 

Selectivity with respect to reagents leads to specificity with respect to products, exemplified by non-statistical branching ratios, anisotropy of angular distribution and "surprising" product state distributions. The importance of vector correlations (from crossed beam experiments with polarized laser-induced fluorescence detection) is touched upon, as well as the subject of polarized laser photofragmentation dynamics (half-collisions) leading to (non-statistical) specificity in product polarizations. 

FIGURE 3, Highly schematic ( ) portrayal of the experimental arrangement [62] for the polarized laser photofragmentation of oriented CH3I molecules. The iodine atoms formed from the 1-photon photodissociation are detected by a 2+1 resonance-enhanced MPI process at an appropriate I atom resonance wavelength. [Reprinted from Ref. 

TABLE 1. Experimental results (Ref. 62) on the asymmetry of the polarized laser photofragmentation of oriented CH3I molecules in selected JKM> "parent rotational states. (The measured up/down ratios have an uncertainty of ca. 10%). 

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