Table of Contents
Laser Chemistry
Volume 8, Issue 2-4, Pages 193-209

Nonlinear Absorption and Far-Infrared Generation Under the Excitation of Ammonia Molecules by Strong IR Radiation

Institute of Spectroscopy, Moscow Region, Troitsk 142092, Russia

Received 20 August 1987; Accepted 28 September 1987

Copyright © 1988 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


We have investigated the excitation of N14H3 molecules (the pressure is 10−2 − 1 Torr) under the effect of pulse radiation of the CO2-laser in a wide range of fluences (Φ = 10−3−10 J/cm2) and detunings of the laser frequency from the absorption lines of the vibrational-rotational transition of the ammonia band ν2. It is shown that the efficient excitation of ammonia under the influence of nonresonance IR radiation is due to the power broadening. In this case the calculation, which employs no fitting parameters, describes the experimental results within experimental errors. It is shown that the abnormally high absorption of ammonia in the case of resonance pumping is associated with an intense FIR generation which leads to elimination of the rotational bottle neck under the excitation of molecules.