ABSTRACT
The differential cross section for the H + D(2) --> HD + D reaction has been measured using a technique called reaction product imaging. In this experiment, a photolytically produced beam of hydrogen (H) atoms crossed a beam of cold deuterium (D(2)) molecules. Product D atoms were ionized at the intersection of the two particle beams and accelerated toward a position-sensitive detector. The ion images appearing on the detector are two-dimensional projections of the three-dimensional velocity distribution of the D atom products. The reaction was studied at nominal center-of-mass collision energies of 0.54 and 1.29 electron volts. At the lower collision energy, the measured differential cross section for D atom production, summed over all final states of the HD(v,J) product, is in good agreement with recent quasi-classical trajectory calculations. At the higher collision energy, the agreement between the theoretical predictions and experimental results is less favorable.
ABSTRACT
Limits of detection for a number of elements both in air and in argon inductively coupled plasma atomic emission spectroscopy (ICPAES) have been determined using a high-resolution interferometric spectrometer (HiRIS) that consists of an acousto-optic tunable filter, a fiber-optic Fabry-Perot interferometer, and a photon-counting PMT detector. Detection limits using the HiRIS are comparable to those determined using a 1.5 m focal-length grating spectrometer, which has resolution similar to that of the HiRIS. Differences between the two spectrometer systems and the two plasma systems are discussed. The portability and versatility of the HiRIS make it a useful alternative for field or on-line measurements using ICPAES. The high-resolution capabilities allow the HiRIS to replace large grating spectrometers for resolution of isotopic and complex spectra.