LOCAL LASER SUPERHEATING DUE TO QUENCHING DETERMINED BY DEGENERATE 4-WAVE-MIXING AND ABSORPTION THERMOMETRY

We used degenerate four-wave-mixing (DFWM) spectroscopy to measure the rotational distribution of transient formed NaH molecules in the Na(3 p)-H-2 collision system applying a recently developed new method for t he correct consideration of the transition dipole moment. Considering the NaH molecule as a thermometric species, we found high rotational t emperatures differing significantly from the oven temperature by up to 80%. For comparison the revealed temperatures were also determined wi th linear absorption measurements giving excellent agreement between t he two methods. The increased temperatures are explained by a spatiall y localized heating mechanism which is caused by kinetic energy transf er between Na(3p) and H-2. A rate equation model, which includes quenc hing and reaction processes, agrees satisfactorily with all types of c hosen parameters, including different sodium excitations as well as di fferent cell temperatures.