RADIATIVE DECAY PROCESSES IN THE 6S AND 7S RYDBERG STATES OF NO STUDIED BY 3-COLOR LASER-INDUCED AMPLIFIED SPONTANEOUS EMISSION-SPECTROSCOPY

A novel spectroscopic technique involving amplified spontaneous emissi on (ASE) is presented to excite single rotational levels of the 6s sig ma T (2)Sigma (+) and 7s sigma Z (2)Sigma(+) Rydberg states of the NO molecule. In this excitation regime, the 3p pi D (2)Sigma(+) state, wh ich is populated by the ASE deexcitation process from the 4s sigma E ( 2)Sigma(+) Rydberg state, serves as the intermediate state. As the ini tial radiative decay channels form the T (2)Sigma(+) and Z (2)Sigma(+) states, the dipole allowed ASE transitions down to the nearest Rydber g states, i.e., T (2)Sigma(+)-->5p sigma R (2)Sigma(+) and Z (2)Sigma( + __)> 6p sigma Y (2)Sigma(+), are identified. The anomalous intensity distributions both in the excitation and emission spectra are well ex plained by s-d mixing and I uncoupling in the upper Rydberg states. (C ) 1998 American Institute of Physics.