T. YAMAZAKI*, B. KETZER**, E. WIDMANN*, J. EADES* (*CERN), H. DANIEL**, F. J. HARTMANN**, M. HASINOFF**, R. POHL**, R. SCHMIDT**, T. von EGIDY** (**Munchen Tech. Univ.), D. HORVATH (KFKI Inst.), M. KUMAKURA, N. MORITA, I. SUGAIÝ, Y. FUJITAÝ (ÝINS, Tokyo Univ.), H. A. TORIIÝÝ, M. HORIÝÝ, T. ISHIKAWAÝÝ, F. E. MAASÝÝ, H. TAMURAÝÝ and R. S. HAYANOÝÝ (ÝÝUniv. Tokyo)
[Chem. Phys. Lett. 265, 137 (1997)]
We have employed a laser resonance method to study the interactions of individual states of metastable antiprotonic atomcules p4He+ with surrounding H2 molecules. We have found that the lifetime of the (n,l) = (37,34) -> (39,35) states are shortened by small admixtures of H2 molecules in quite different ways; the observed quenching cross section for the upper (39,35) state in helium medium at 1 bar and 30K is (2.4 ±1.0) * 10-15cm2, a factor of 24 larger than that for the lower (37,34) state.