Rotational coupling of the β 1 and E 0 + ion-pair states of lodine bromide

Abstract

The E( Ω = 0 +) and β( Ω = 1) ion-pair states of IBr are coupled by an electronic Coriolis interaction. A nonlinear, least-squares fit of term values for both states yields a set of potential and rotational constants purged of the effects of this interaction. The magnitude of the coupling constant, | W 1,0| = 2.41 cm −1, is 98% of the value predicted for pure precession. Principal constants of the previously unreported β state of I 79Br are T e = 39507.76, ω e = 122.09, ω e χ e = 0.2546, B e = 0.02937, and α e = 8.2 × 10 −4cm −1.