title: Experimental detection and theoretical characterization of the H2-NHX van der Waals complex.
abstract: The H2-NH(X) van der Waals complex has been examined using ab initio theory and detected via fluorescence excitation spectroscopy of the A(3)Pi-X(3)Sigma(-) transition. Electronic structure calculations show that the minimum energy geometry corresponds to collinear H2-NH(X), with a well depth of D(e)=116 cm(-1). The potential-energy surface supports a secondary minimum for a T-shaped geometry, where the H atom of NH points towards the middle of the H2 bond (C(2v) point group). For this geometry the well depth is 73 cm(-1). The laser excitation spectra for the complex show transitions to the H2+NH(A) dissociative continuum. The onset of the continuum establishes a binding energy of D(0)=32+/-2 cm(-1) for H2-NH(X). The fluorescence from bound levels of H2-NH(A) was not detected, most probably due to the rapid reactive decay [H2-NH(A)-->H+NH2]. The complex appears to be a promising candidate for studies of the photoinitiated H2+NH abstraction reaction under conditions were the reactants are prealigned by the van der Waals forces.
authors.affiliation: Department of Chemistry, Cherry L. Emerson Center for Scientific Computation, Emory University, Atlanta, Georgia 30322, USA.
authors.forename: Wafaa M
authors.initials: WM
authors.lastname: Fawzy
authors.forename: Galina
authors.initials: G
authors.lastname: Kerenskaya
authors.forename: Michael C
authors.initials: MC
authors.lastname: Heaven