SPECTROSCOPY OF DOUBLY RESONANT 3RD-HARMONIC GENERATION IN I-2

A technique of third-harmonic generation based on simultaneous resonances in one- and two-quantum transitions was applied to find a level of symmetry Og+1 of molecular iodine. The energy of this level is given, in cm-1, by ET(n,J)=(35 972.40.5)+(132.90.2)(n+12)-(0.340.02)(n+12)2+[(0.028 570.000 15)-(0.000 150.000 02)n](J)(J+1), where n is an integer differing from the vibrational quantum number v by an undetermined integer and J is the angular momentum. This technique has relatively high efficiency in third-harmonic generation and may provide a basis for a new Doppler-free spectroscopy. © 1979 The American Physical Society.