Relaxation rotationnelle de H2CO due à la détente du gaz

Abstract

We study the rotation–translation energy transfer on an expansive formaldehyde beam. On this beam, we measure the translational and rotational temperatures with RF spectroscopy methods. We can verify that we are dealing with isenthalpic expansion. Comparing experimental and theoretical results, we determine the cross section of rotation–translation energy transfer (σr = 23 Å2) for H2CO–H2CO collisions and the rotational coupling parameter [Formula: see text].