Rotational relaxation in free jet expansion for N/sub 2/ from 300 to 1000 K

Journal Article · Wed Apr 15 04:00:00 EST 1981 · J. Chem. Phys.; (United States)

OSTI ID:6439154

Yamazaki, S; Taki, M; Fujitani, Y

The object of this study is to obtain information on the rotation--translation transition probability during N/sub 2/--N/sub 2/ collisions. Rotational relaxation for N/sub 2/ in the free expansion flow is studied by TOF (time-of-flight) measurement with a molecular beam sampling mass filter system. Source temperatures were heated up to 1300 K by an electric heater. The terminal rotational temperatures for various source temperatures and pressures were determined from an energy balance equation in conjunction with the TOF data. Recently, Pritchard et al. have proposed that the transition probability from the ith to the jth rotational states decreases in proportion to some power of the energy difference between the states. This power law was fitted to experimental results for rotational relaxation in the free jet expansion. The results show that the state-to-state rotational relaxation rates vary as the inverse 3/2 power of the energy difference between the initial and final states. The rotational distributions in the jet expansion were also calculated by this power law. The results show a Boltzmann distribution for low j levels but not for high j levels.

• Research Organization: Toyota Central Research and Development Laboratories, Inc., Nagakute-cho, Aichi-gun, Aichi-ken, 480-11, Japan
• OSTI ID: 6439154
• Journal Information: J. Chem. Phys.; (United States), Journal Name: J. Chem. Phys.; (United States) Vol. 74:8; ISSN JCPSA
• Country of Publication: United States
• Language: English

Related Subjects

640304* -- Atomic
Molecular & Chemical Physics-- Collision Phenomena
74 ATOMIC AND MOLECULAR PHYSICS
BEAMS
COLLISIONS
ELEMENTS
ENERGY LEVELS
ENERGY TRANSFER
EXCITED STATES
EXPANSION
HIGH TEMPERATURE
JETS
MEDIUM TEMPERATURE
MOLECULAR BEAMS
MOLECULE COLLISIONS
MOLECULE-MOLECULE COLLISIONS
NITROGEN
NONMETALS
RELAXATION
ROTATIONAL STATES