On the intensity distribution among the lines of certain bands in the spectrum of the hydrogen molecule

There is a definite alternation of intensity in the successive lines of a given branch of this spectrum. This is particularly evident in the Q branches, which are the strongest, the lines usually denoted by Q (1), Q (3) and Q (5) being much more intense than the intervening lines Q (2) and Q (4). For some time I have had evidence which, though in some respects incomplete, pointed to the con­clusion that in any band the mean value of the intensities of any two consecutive odd-numbered lines such as Q (1) and Q (3) was nearly equal to three times the intensity of the intervening line such as Q (2). An examination of the much more comprehensive measurements which have recently been obtained by McLennan, Grayson-Smith and Collins seems to remove all doubt from this matter. In the second row of Table I, I tabulatea the sums of their measured inten­sities of the lines Q (1) and Q (3) for the successive bands denoted by0 x 0 ,1 x 1 ,2 x 2 ,3 x 3 and4 x 4 in Structure, Part V. These are followed in the third row byb , twice the intensity as measured of the corresponding Q (2) line. The fourth row contains the resulting values ofb ÷a . All the foregoing are the data got at Boom Temperature (R. T.). These are followed in the same order by similar data got with the thin-walled discharge tube immersed in liquid air (L. A.). Finally, the eighth row contains the average of the two values ofb ÷a got at the two temperatures.