In order to excite some molecules besides 11SCl3vibrationally, a line selective CO2 laser has been constructed. Maximum cw output at each band through a main mirror, of 91.5 reflection is 16, 12, 7and 6.5W/line for 9.2, 9.6, 10.2 and 10.6μm band, respectively, and the total number of generated lines is 84. No spectral change is observed in the selective excitations of 11BCl3, 10BCl3 and 32SF6 in Xe matrix at 47 K. However, by temperature rise under successive irradiation, the peak height of crystalline 11BCl3 increases remarkably at 76-80K, and reaches the maximum value at 100 K. It is found that the pulsed irradiation is effective for the selective excitation of 11BCl3 or 10BCl3. In the case of 32SF6 excitation, pre-irradiadiation with a cw CO2 laser at 47 K promotes the crystallization of 32SF6 by a temperature rise of the sample. This implies the fact. that vibrationally excited 32SF6 molecules have been gathered to form the crystal readily.
