ATMOSPHERIC SCIENCES

ATMOSPHERIC CARBON MONOXIDE (CO) IS IMPORTANT BOTH AS AN ANTHROPOGENIC POLLUTANT AND AS A PARTICIPANT IN THE PHOTOCHEMISTRY OF THE (NOMINALLY) UNPOLLUTED ATMOSPHERE. INTHE LATTER CONTEXT, THERE EXISTS A NEED FOR A SIMPLE AND CONVENIENT INSTRUMENT TO MEASURE CO CONCENTRATIONS IN THE RANGE OF A FEW TENS OF PPB. WE PROPOSE TO DO THIS BY MEASURING THE ABSORPTION, BY THE INFRARED R16 LINE OF CO, OF THE NEUTRAL XENON LASER LINE AT 2202.99 CM(-1). TO ACHIEVE PRECISE COINCIDENCE BETWEEN THE LASER AND ABSORPTION LINES WILL REQUIRE THAT THE LASER FREQUENCY BE SHIFTED USING THE ZEEMAN EFFECT, AND THE PRACTICALITY OF THE PROPOSED TECHNIQUE DEPENDS ON BEING ABLETO OPERATE THE LASER AT THE REQUIRED MAGNETIC FIELD, APPROXIMATELY 4,100 GAUSS. IN THE PROPOSED RESEARCH, WE WILL DETERMINE THE OPERATING CHARACTERISTICS OF THE LASER, IN ZERO FIELD AND AT FIELD STRENGTHS UP TO THAT REQUIRED TO ACHIEVE COINCIDENCE BETWEENTHE LASER AND ABSORPTION LINES.