is used to measure the radiation received see the chemists companion a j gordon amp r a ford wiley interscience 1972 pages 362 368 in this vessel under these conditions this procedure gives an incident light intensity of 1 317 u00d7 10 u2212 7 einstein sec 0 0417 watts one einstein is equal to a mol of photons a five minute exposure should therefore supply 3 95 u00d7 10 u2212 5 einsteins of light 0 039 watt hour kg after exposure the vapor head of the pressure vessel is sampled by gas chromatography the photochlorination of r 365mfc is carried out in a 125 ml pyrex pressure vessel equipped with an inlet at the bottom and an outlet at the top the reactor vessel is placed at the focus of rpr 100 rayonet reactor southern new england ultraviolet company equipped with 16 rpr 3500 lamps having their peak intensity at a wavelength of 350 nm the pyrex walls of the pressure vessel remove light below 300 nm the vessel is immersed in a pyrex constant temperature bath held at 59 u00b0 c to ensure that the r 365mfc remains in the vapor phase two feed streams are passed through separate lengths of capillary tubing and then mixed and passed into the reactor at 5 psig 34 5 kpa gauge the impure r 365mfc contains 0 08 r.