The infrared absorption spectrum in the 16-17 pm region of the transient UFS mofecutc formed from laser photol~s~s of UF6 is presented. The absorption contour and the intensity measurements allow tentatire assignment of the molecular structure.
In a previous paper Elf we have reported a partial infrared spectrum in the 17 cun region of the UF5 moiecule formed from the laser fIash photolysis of UF, _ Tine sample cell, which has a 10 m basic physica length, allowed us to observe the formed UFs molecute both under collision free conditions and at intermediate pressures_ In the present communication we wish to report the detailed infrared spectrum of the UF5 molecule covering both 16 w and 17 pm re-gions_ and present a tentative assignment of the molecular structure_
Low pressure samples of pure UF6 (typlcafly less than 2 X 10-Z Torr) were flash photolyzed [I ] using a Lambda Physik KrF laser operating at 248 nm with d puIse energy of 100-200 mJ. The diagnostic probe consisted of a tunabte semiconductor Iaser operating cw in tlte 16-I 7 elm region. The diode beam was made collinear with the KrF laser radiation inside the cell. After the optical path length of 10 m the exciting IR beam was dispersed by a 1 m monochromator and detected by a fast HgCdTe detection system. The time resolved photoiysis event was then processed and averaged using a LeCroy waveform digitizer-microcomputer system.
Experimental measurements consisred of(i) the depletion of UF6 in the I6 pm region and (ii) the absorption of UFs in the 17 pm region. Fig. I shows typical * %rk performed under the auspices of the U.S. DOE.