Related Experiment Video
Updated: Jun 12, 2026

Direct Imaging of Laser-driven Ultrafast Molecular Rotation
Published on: February 4, 2017
Effects of translational and rotational nonequilibrium on cw chemical laser performance
Abstract:
A previous model used to describe cw chemical laser performance is generalized to include rotational as well as translational nonequilibria. The resultant equations are simplified by the realistic assumption that translational and rotational relaxation rates are fast compared with convection, chemical pumping, and collisional deactivation rates. As a consequence, translational and rotational relaxation are in equilibrium with stimulated emission. A further simplification is introduced by the assumption |1-(R(t)/R(r))|(Delta nu (h)/Delta nu (d) << 1, where R(t)/R(r) is the ratio of translational to rotational relaxation rates, and Delta nu (h)/Delta nu (d) is the ratio of homogeneous to Doppler widths. The resultant system of equations is independent of rotational relaxation. An amplifier solution is presented that predicts saturation effects in accord with experiments. Fabry-Perot oscillator solutions are also presented for a multiline saturated laser and a partly saturated single-line laser. The present results provide a basis for simplification of numerical codes. It is concluded that a reasonable first estimate for cw chemical laser performance can be obtained by assuming rotational equilibrium and translational nonequilibrium.
Related Concept Videos
Standing Waves in a Cavity
Disubstituted Cyclohexanes: cis-trans Isomerism
In cyclohexane, the substituents can occupy different positions generating distinct isomers.
Thermal Electrocyclic Reactions: Stereochemistry
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation
Atomic Nuclei: Larmor Precession Frequency
¹H NMR: Interpreting Distorted and Overlapping Signals
As Δν decreases and the signals move closer, the doublets appear increasingly distorted. The intensities of the inner lines increase at the cost of those of the outer lines as the signals are slanted or...

