Photodissociation of diiodomethane by using cavity ring down spectroscopy
|Keywords:||腔體震盪光譜法;光解;二碘甲烷;碘分子;單分子解離;CRDS;photodissociation;diiodomethane;iodine;unimolecular dissociation||Issue Date:||2010||Abstract:||
Cavity ring-down spectroscopy (CRDS) is a relatively new and quite sensitive technique for the measurement of gas phase. It holds the potential for simple, direct and sensitive measurement of the concentrations of a variety of trace gases in the atmosphere. In this thesis, We used CRDS to detect I2 produced from photodissociation of CH2I2. We can confirm this primary dissociation channel by energy dependence and pressure dependence experiments. The vibrational population ratio was found to be v0:v1:v2=1:0.65±0.1:0.3±0.05 .The quantum yield for the I2 elimination reaction is determined to be 0.004±0.002. We propose I2 elimination may process through the electronic ground state by internal conversion. This hypothesis is supported by the result of temperature dependence experiment. Moreover, the results agree with a given theoretical calculation.
|Appears in Collections:||化學系|
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