Microwave spectrum of Ne:HBr: structural perspectives on Rg:HX, Rg = Ne, Ar, Kr; X = F, Cl, Br, I

Microwave spectra of ground state 20Ne:1H79Br, 20Ne:1H81Br, 22Ne:1H79Br, 22Ne:1H81Br, and their corresponding deuterated isotopomers are obtained using pulsed-nozzle Fourier Transform microwave spectroscopy. The 20Ne:1H79Br ground state 〈 P 2 ( cos θ ′ ) 〉 = 0.09025 ( 11 ) is characteristic of a nearly free rotor. The available 20Ne:1H79Br, 20Ne:2H79Br, 22Ne:1H79Br and 22Ne:2H79Br data are analyzed and used to determine an initial ground vibrational state morphed potential for the dimer. This resulting intermolecular potential indicates a global minimum Ne:BrH linear isomeric structure with Rcm = 3.42 Å. These analyses also provide structural perspectives on the prototypical homologous series Rg:HX (Rg = Ne, Ar, Kr; X = F, Cl, Br, I).