| 摘要 |
<p>A method of separating isotopes from polyatomic molecules, in particular 13C from trifluoromethane HCF¿3?, by applying to the polyatomic molecules in the gas phase two infrared laser beams of different frequencies. The first laser has a frequency appropriate to excite a low overtone transition of a light atom stretch vibration and produce vibrationally pre-excited molecules enriched in the desired isotope, for instance ?13¿C. The second laser has a frequency and energy fluence to selectively induce dissociation of the vibrationally pre-excited molecules by infrared multiphoton excitation. The product of the pressure of the molecules and the time-delay of the second laser pulse relative to the first allows collisional vibrational deactivation of a substantial amount of the vibrationally pre-excited molecules containing non-desired isotope(s), like 12C, before dissociation of the vibrationally excited molecules occurs, while there is no significant collisional vibrational deactivation of pre-excited molecules containing the desired isotope, like 13C. The dissociation products are hence highly enriched in the desired isotope.</p> |
