Rotational band contour analysis in the 3120 Å system of naphthalene

The rotational contour of the 0 + 435 cm-1 (440 1) type B band of the Ã1B2u - X1Ag system of naphthalene has been analysed by the method of computer simulation. The resulting rotational constants are considerably different from previously reported values. With the new values agreement between the observed 00 0 band contour and a computed type A rather than a type C contour is now clear-cut, confirming previous assignments. The wavenumber of the rotational origin of the 00 0 band is shown to be 32018·53 ± 0·04 cm-1 and that of the 440 1 band is 32453·50 ± 0·04 cm-1.