4.5 mu m diode laser spectrum of (HI)(2)

The 4.5 mu m infrared spectrum of (HI)(2) has been recorded using a superso nic jet diode laser spectrometer. The spectrum assigned to the nu(2)(+) ban d is interpreted as being associated with a ground state rotational constan t, B-0 = 378.438(50) MHz, corresponding distortion constant, D-J(0) = 0.402 (20) kHz, band origin, nu(0)(nu(2)(+)) = 2217.30262(7) cm(-1) and a R-cm di stance of 4.563(2) Angstrom. Combination bands originating from the ground state are assigned with nu(0) = 2234.75157(6) cm(-1) and nu(0) = 2233.65326 (9) cm(-1) respectively. Observed spectra are consistent with the tunneling dynamics for other members of the homologous series (HX)(2), X = Cl and Br . (C) 2000 Published by Elsevier Science B.V.