COLLISIONAL DESTRUCTION of FeCn (n = 1 to 4, 6) ANIONS of ASTROPHYSICAL RELEVANCE

The stability of FeC- against dissociation in an astrophysical environment was probed by the collisional excitation of FeC-. Two anion resonances yielding Fe- and C- fragments were observed and studied through measurement of the kinetic energy released during fragmentation. The yield of Fe- was found to be nearly 5.5 times more than that of C- indicating the C- fragment to be in the loosely bound (2D) state. The possibility of avoided crossing leading to the observed fragment ion yield is also discussed. The dissociation of FeCn(n = 2 to 4, 6) cluster anions predominantly resulted in the cleavage of Fe-C bond yielding only fragments with similar energy release. The yield of Cn is discussed in the light of the observed abundances of HCn in IRC+10216. The importance of rotational transitions pertaining to both the ground and excited-electronic states of these cluster anions is discussed.