It has recently been demonstrated that efficient separation of isotopic spccies can be achieved by selective, laser-induced multiphoton vibrational excitation of polyatomic molecules.1,2Examples of separations reported to date include isotopes ofhydrogen,3 boron,4 carbon,4b silicon,4b sulfur,5 chlorine,5 se-lenium,7 molybdenum,8 and osmium.9 The key molecular re-quirements for such a process are volatility and the existenceof an infrared-active normal vibrational mode (fundamental, overtone,6b,8 or combination6b,8) which exhibits a nonzeroisotopic shift. The molecular infrared absorption is broughtinto coincidence or near coincidence in the gas phase with anintense (~107-109 W/cm2) infrared laser source, resulting inisotopically selective decomposition or reaction. To date, most laser-induced isotope separation (LIS) experiments have beenperformed with pulsed, discretely tunable CO2 infrared gaslasers. These devices have a usable output in the 10-µ region(9.2-10.8 µ) and are by far the most powerful, reliable, monochromatic, and economical sources of mid-infrared laserradiation presently available.
ASJC Scopus subject areas
- Colloid and Surface Chemistry