Experimental study of the intensity theories in band spectra: I, Hutchisson's theory; II, Langstroth's theory

The Second Positive system of N 2 was excited in a wide-bore discharge tube of the H-type by means of an induction coil, the primary supply for which was 10 volts at 1.5 amp.; no spark gap or condenser was included in the secondary circuit. Integrated intensity values for all the measurable bands of the system were determined by photographic photometry. Transition probabilities for bands in emission are calculated from known molecular constants, with the help of the formula suggested by Hutchisson. Observed I /ν 4 values (where I is the integrated intensity) for bands belonging to different ν''-progressions are compared with the calculated emission-probabilities, and it is found that the agreement is not satisfactory. The agreement is considerably improved by interchanging the vibrational quantum numbers. Some of the factors responsible for the apparent failure of the theoretical treatment are discussed, and a probable reason for the improvement in agreement between the observed and calculated values on interchange of ν' and ν'' is suggested.