Jb. Davey et al., Interaction of water and dichlorine in the gas phase: An investigation of H2O center dot Cl-2 by rotational spectroscopy and ab initio calculations, J CHEM PHYS, 114(14), 2001, pp. 6190-6202
Ground-state rotational spectra of the seven isotopomers H2O . . . Cl-35(2)
, H2O . . . (ClCl)-Cl-37-Cl-35, H2O . . . (ClCl)-Cl-35-Cl-37, D2O . . . Cl-
35(2), D2O . . . (ClCl)-Cl-37-Cl-35, HDO . . . Cl-35(2), and HDO . . . (ClC
l)-Cl-37-Cl-35 of the complex formed between water and dichlorine were obse
rved by pulsed-jet, Fourier-transform microwave spectroscopy. Rotational co
nstants B-0 and C-0, centrifugal distortion constants Delta (J) and Delta (
JK), and Cl nuclear quadrupole coupling constants chi (aa)(Cl-x) and {chi (
bb)(Cl-x)-chi (cc)(Cl-x)}, where x=i (inner) or o (outer), were obtained vi
a spectral analyses. The spectroscopic constants were interpreted, on the b
asis of models for the complex, to give the geometry, the binding strength,
and the extent of inter- and intramolecular electron transfer on complex f
ormation. The zero-point geometry is defined in terms of the effective valu
es r(O . . . Cl-i)=2.8479(3) Angstrom and phi =43.4(3)degrees, where phi is
the angle made by the bisector of the HOH angle with the O . . . Cl intern
uclear line. The intermolecular stretching force constant k(sigma)=8.0(1) N
m(-1). Fractions delta (i)=0.005(5) and delta (p)=0.034(3) of an electron
were estimated to be transferred from O to Cl and from Cl-i to Cl-o, respec
tively. The geometrical conclusions are supported by ab initio calculations
at the aug-cc-pVDZ/MP2 level of theory, with good agreement for phi and r(
O . . . Cl-i). A comparison of the properties of H2O . . . Cl-2 with those
of H2O . . . HCl provides evidence in support of a recent proposal of a hal
ogen bond B . . . XY that is the analog of the hydrogen bond B . . . HX, wh
ere X and Y are halogen atoms. (C) 2001 American Institute of Physics.