Rotational band contour analysis of the ùA′-[Xtilde]¹A′ electronic transitions in 1- and 2-chloronaphthalenes

Abstract

The high-resolution electronic bands of the à ¹ A′-[Xtilde] ¹ A′ absorption system of 2-chloro- and 1-chloronaphthalene have been analysed by the method of rotational band contours. The excited state rotational constants of 2-chloronaphthalene may be interpreted in terms of a planar geometry of the molecule in the excited state, but no such explanation seems possible for 1-chloronaphthalene. It is found that the perturbing effect of chlorine substitution on the 312 nm electronic transition of naphthalene is significantly different from that of F, OH and NH₂.