State resolved cross sections for rotationally inelastic collisions of NH/sub 2/(X /sup 2/B/sub 1/) with helium

Journal Article · Wed Mar 01 04:00:00 EST 1989 · J. Chem. Phys.; (United States)

OSTI ID:6532449

Dagdigian, P J

Integral cross sections for rotational transitions from the lowest orthorotational level (0/sub 0,0/) of 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 K/sub a/ = 0 and 1 manifolds of NH/sub 2/ were interrogated in the collision zone by dye laser fluorescence excitation in the A-italic-tilde /sup 2/A/sub 1/left-arrowX /sup 2/B/sub 1/ band system. Because of the rotational selection rules in this band system, it was not possible to put the cross sections for the two K/sub a/ manifolds on the same scale. Within a given K/sub a/ manifold, there is a marked preference for collisional transitions with the smallest ..delta..N change. These experimental results are compared to calculated close-coupling rotationally inelastic cross sections for H/sub 2/O(0/sub 0,0/)--He collisions.

• Research Organization: Department of Chemistry, The Johns Hopkins University, Baltimore, Maryland 21218
• OSTI ID: 6532449
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 90:5; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
ATOM COLLISIONS
ATOM-MOLECULE COLLISIONS
BEAMS
COLLISIONS
CROSS SECTIONS
ELEMENTS
ENERGY LEVELS
ENERGY-LEVEL TRANSITIONS
EXCITED STATES
FLUIDS
GASES
HELIUM
HYDRIDES
HYDROGEN COMPOUNDS
INTEGRAL CROSS SECTIONS
MOLECULAR BEAMS
MOLECULE COLLISIONS
NITROGEN COMPOUNDS
NITROGEN HYDRIDES
NONMETALS
RARE GASES
ROTATIONAL STATES