  A possibility for molecular-nuclear transitions to occur was recently
predicted for some few-atomic systems. Among others, the molecule of ordinary
water was shown to be a candidate for this effect due to a presence of (1-,
4.522 MeV) resonance in 18Ne nucleus. A search for traces of nuclear reactions
was carried out for condenced and vaporous phases of water, with the use of
low-background annihilation spectrometry. The measurements were performed under
conventional conditions and under conditions of the Baksan Neutrino
Observatory.
