Basic Research on Laser Isotope Separation by 2-Color IR Multiple Dissociation.

用TEA CO_2激光器和自由电子激光器（FEL）对BCl_3进行了红外多光子离解和同位素分离实验。获得了以下结果：1）首次利用自由电子激光实现了BCl_3的多光子解离和^<10>B和^<11>B的同位素分离。2）测量了BCl_3的解离产额与激光强度的关系。结果表明，在激光强度超过解离阈值的区域内，对于一个CO_2激光脉冲或一个自由电子激光宏脉冲，BCl_3分子全部解离。BCl_3的工作气压越低，同位素选择性越大。4）双色红外激光辐照大大提高了同位素选择性。

IR multiphoton dissociation and isotope separation experiments of BCl_3 have been performed by using a TEA CO_2 laser and an free electron laser (FEL). The following results were obtained.1) Multiphoton dissociation of BCl_3 and isotope separation of ^<10>B and ^<11>B using an FEL was demonstrated for the first time.2) Dependences of dissociation yields on laser irradiation intensity were measured. It was found that in the region where the laser intensity exceeds the dissociation threshold all the BCl_3 molecules dissociate for one CO_2 laser pulse or for one FEL macropulse.3) The maximum dissociation yield is obtained for the freqeency shift towards the red side from the vibrational resonance of BCl_3. The lower the operation gas pressure of BCl_3, the larger the isotope selectivity.4) The isotope selectivity is greatly improved by 2-color IR laser irradiation.