Observation of the cyclic water hexamer in solid parahydrogen

We present infrared (IR) absorption spectra of cryogenic parahydrogen solid s doped with small water clusters. We observe a sequence of peaks shifted t o the red by approximate to 15 cm(-1) from the absorptions of cyclic water clusters in liquid helium droplets [K. Nauta and R. E. Miller, Science 287, 293 (2000)]; this sequence includes the peak due to the cyclic isomer of t he water hexamer: cyc-(H2O)(6). We believe this is only the second spectros copic observation of isolated cyc-(H2O)(6), and the first report of the IR spectrum of the isolated cluster in the solid phase. (C) 2001 American Inst itute of Physics.