Temperature effects, during irradiation

For irradiation at 313 m/, the reactor consisted of a 6- X 2-inch o.d. cylindrical borosilicate glass tube fitted directly to the mass spectrometer by a 24/40 joint. A Hanovia analytical lamp, having an estimated output of 325 watts, was mounted externally alongside the tube. The radiation received by the samples inside the tube was filtered through borosilicate glass and was essentially 313 m/. The ambient temperature within the reactor during irradiation was 25 °C. Some comparative experiments were carried out at 70 °C. with additional heating. There was no detectable temperature effect between 25° and 70°C., and the results reported here are for 25 °C. 

Temperature control during irradiation was effected by placing the tubes in holes in a thermostatted aluminum block. 

The multiphoton absorption cycle was confirmed by a comparison of the temporal profile of the fluorescence of anthracene-doped polystyrene films with computational results based on the cyclic process [97]. In the computational studies, the ground state, first excited singlet state, and lowest triplet state have been included. The calculated temperature rise during the laser pulse depends nonlinearly on the laser intensity. Rapid internal conversion within the triplet manifold is the most effective mechanism for depositing heat at the irradiated surface. 

---