Skip to main content
U.S. Department of Energy
Office of Scientific and Technical Information

State-resolved cross sections for rotationally inelastic collisions of NH sub 2 (x2B1 state) with helium

Technical Report ·
OSTI ID:5596861
Integral cross sections for rotational transitions from the lowest orthorotational level (zero 0,0) of Amidogen (NH{sub 2}) induced by collisions with helium have been measured in a crossed beam experiment. A pulsed supersonic beam of rotationally cold NH{sub 2} was produced by 193 nm photolysis of a dilute mixture of ammonia in argon seed gas at the tip of a nozzle; the helium target was also prepared as a pulsed beam. The final rotational state populations (without spin-state resolution) in the Ka = 0 and 1 manifolds of NH{sub 2} were interrogated in the collision zone by dye laser fluorescence excitation in the A2A1 yields X2B1 reverse band system. Because of the rotational selection rules in the band system, it was not possible to put the cross sections for the two Ka manifolds on the same scale. Within a given Ka manifold, there is a marked preference for collisional transitions with the smallest DeltaN change. These experimental results are compared to calculated close-coupling rotationally inelastic cross sections for H{sub 2}O (zero 0,0 state)-helium collisions.
Research Organization:
Johns Hopkins Univ., Baltimore, MD (USA). Dept. of Chemistry
OSTI ID:
5596861
Report Number(s):
AD-A-209466/2/XAB
Country of Publication:
United States
Language:
English