Experimental Studies of the Properties of Trihydrogen and Tetrahydrogen

摘要

Results of theoretical calculations by Nicolaides et al. have suggested theexistence of metastable tetrahydrogen (H4) molecules. The specific impulse of this species is estimated to be 1820 s, making it a very interesting candidate for a rocket propulsion system. The scattered products of the H3 + HI collisions are measured with the help of an electron bombardment quadrupole mass spectrometer, having two angular motion degrees of freedom. This complex apparatus was put together and made operational. Preliminary experiments were then performed and the results indicated that it would indeed permit the proposed reaction to be investigated in detail. At this point, further more accurate calculations by Montgomery et al. found that H4 in the 1A' state is not bound. This result led us to concentrate on studying the properties of the metastable H3 beam. A sophisticated apparatus to produce and characterize a metastable beam of H3 molecules were designed, constructed and assembled. It consists of an archeated metastable H3 beam source, a Stern-Gerlach magnetic velocity selector and an electron bombardment mass spectrometer detector. The resolution of the latter still needs improvement. Once this is achieved, experiments will be performed to determine the rovibrational composition, translation energy distribution, and radiative lifetime of the metastable Hs beam and to determine its chemical properties. (TTL)