New Measurements in the Fourth Positive CO Bands

That part of the fourth positive system of CO lying between 1970A and 2800A has been remeasured together with sixteen bands not previously observed. An equation for the band heads is given, the constants of which yield the values D^'=12.00 volts, D^''=11.17 volts for the heat of dissociation.Modifications in values of frequency have been small, while those of intensity have been rather large. Some discrepancies have been removed. Revision of intensity estimates permits a far more accurate comparison than previously with Condon's theory of intensity distribution and shows the superiority of Morse's $U(r)$ function. Using this function, the distribution of intensity among the bands of the fourth positive system agrees perfectly with Snow and Rideal's value of the moment of inertia for the normal state, I₀^_^''=15.0×10^-40 g cm².The quantum assignment of Asundi's infra-red electronic bands has been revised.