Reaction product imaging : the H + D2 reaction

• Published in: Science (American Association for the Advancement of Science) 1993-06, Vol.260 (5114), p.1605-1610
• Main Authors: KITSOPOULOS, T. N, BUNTINE, M. A, BALDWIN, D. P, ZARE, R. N, CHANDLER, D. W
• Format: Article
• Language: English
• Subjects: Atomic and molecular collision processes and interactions; Atomic and molecular physics; Chemical reactions; Exact sciences and technology; Physics; Scattering of atoms, molecules and ions
• ISSN: 0036-8075; 1095-9203
• DOI: 10.1126/science.260.5114.1605

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.