Experimental and ab initio equilibrium structure of trans-diazene HNNH

The experimental r(z) and r(e) structures of trans-diazene have been calculated using the experimental ground state rotational constants of N2H2, N2D2 and N2DH and a newly determined harmonic force field. For comparison the structure has been calculated ab initio at the MP2, CCSD and CCSD(T) levels using a polarized triple-zeta basis set. The average geometry is determined to be: r(2)(N-H) = 1.041(1) Angstrom, r(z)(N=N) = 1.252(1) Angstrom and angle(HNN) = 106.3(1)degrees and the equilibrium one: r(e)(N-H) = 1.029(1) Angstrom, r(e)(N=N) = 1.247(1) Angstrom and angle(HNN) = 106.3(1)degrees. The Coriolis interacting bands in HNNH, DNND and HNND were reanalysed using the Coriolis constants calculated from the force field. (C) 1997 Elsevier Science B.V.