| Abstract: | Conclusions The phase method can be applied to other compounds, but the choice of molecules and vibrational levels is restricted by the need for the level to have two allowed IR transitions. Also, the use of the method is restricted by the availability of strong IR sources.The phase method is analogous in concept to the spectrophone method I] The advantage of the phase method is that it allows measurement of the lifetime for a single level no matter where it lies in the system of vibrational levels. Cascade transitions in deactivation (stepwise transformation of vibration energy to heat) greatly complicates the interpretation in the speetrophone method and essentially restricts its use to the first excited levels. Establishment of the phase zero is the main source of error in the spectrophone method and requires special calibration 5]. This problem has a simple solution in the phase method.In some cases the vibrational relaxation time can be determined from the amplitude dependence as affected by pressure, but this requires correction for the pressure dependence of the absorption coefficient for the exciting transition as well as that of the conditions for escape of the spontaneous emission through-out the vibration-rotation band.Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 10, No. 2, pp. 252–255, February, 1969. |
