ROTATIONAL SPECTRUM AND STRUCTURE OF NE-C6H6-H2O, AN AROMATIC SANDWICH

Low J(J = 1 --> 5) rotational spectra of seven isotopomers of Ne-C6H6-H2O trimer have been observed with a Balle/Flygare Fourier transform microwave spectrometer. The trimer is found to be a symmetric top with a B0, D(J), and D(JK) in the parent of 959.3504(1) MHz, 2.425 (2) kHz, and 13.385(5) kHz. The benzene is sandwiched between Ne and H2O, both of which lie on the C6 axis of benzene. Substitution analysis gives the neon and oxygen distances from the trimer center of mass (c.m.) to be 3.324 and 3.454 angstrom, respectively. The Ne to c.m. (C6H6) and c.m. (C6H6) to C.M. (H2O) distances thereby determined are 3.391 and 3.334 angstrom, respectively. Those in the corresponding dimers are 3.458 and 3.329 angstrom, giving a decrease in the trimer of 0.067 angstrom in the Ne to c.m. (C6H6) distance and an increase of 0.005 angstrom in c.m. (C6H6) to c.m. (H2O). Otherwise the state of the water in the dimer does not appear to be materially affected by addition of the Ne.