Conformation-selective photoionization of covalently-linked diaryl compounds: Excimer-mediated one-color two-photon ionization in seeded beams of 1,3-diphenylpropane Excited stateselected transition metal cations from onecolor UV multiphoton ionization A one-color photolysis-ionization study of the photodissociation of hydrazoic acid near 283 nm has been carried out. The N2 and NH(a I~) products have both been detected in a state-specific manner by resonance-enhanced multiphoton ionization (REMPI) in a time-of-flight mass spectrometer. The N2 fragments were observed in the v = 0 vibrational mainfold and were found to be highly rotationally excited, with an average rotational excitation of 0.79 eV. The p-J correlation parameter J

The use of phase-sensitive receiver can lead to errors in the measurement of the acoustic absorption coefficients of inhomogeneous samples. The problem can be avoided by use of a radiation force or an acoustoelectric receiver. Subject Classification: 80.30, 80.20.

An anisotropic spatial velocity distribution was observed for NO+ produced following one-color photolysis/ionization of tert-butyl nitrite (TBN) by a pulsed polarized laser at 266, 355 and 532 nm in a time-of-flight mass spectrometer. The dependence of the NO+ fragment mass peak profile on the wavelength and on the polarization was monitored. The most striking feature is the varying fragment peak splitting obtained under the same experimental conditions by changing the laser polarization direction. This phenomenon is a result of the vector correlation between the laser polarization,Ê, at a given wavelength, the electronic transition dipole moment of TBN,μ, and the direction of the NO fragment velocity, v. The dynamics of the photodissociation process and, in particular, its directional properties are discussed in view of these results.

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