Precision measurements of NH(3) spectral lines near 11 microm using the infrared heterodyne technique.
Absolute line-center frequencies for eleven lines of ammonia in near coincidence with CO(2)-laser transitions have been determined to accuracies of +/-3 MHz by infrared heterodyne detection. These results were obtained by heterodyning a blackbody with a stable, grating-tuned CO(2) gas laser. A discussion of the apparatus and method of calculation, including error analysis, is presented. With these accurately determined line-center positions, the ammonia molecule will be a useful secondary-frequency standard for diode-laser spectroscopy in the 11-microm wavelength region.
Hillman
J J
JJ
Kostiuk
T
T
Buhl
D
D
Faris
J L
JL
Novaco
J C
JC
Mumma
M J
MJ