THE IDENTIFICATION OF THE FEH2 RADICAL IN THE GAS-PHASE BY INFRARED-SPECTROSCOPY

The FeH2 radical has been detected in the gas phase through the observ ation of transitions in the fundamental band of the antisymmetric stre tching vibration nu(3). The molecule was generated in an electrical di scharge through a mixture of hydrogen and iron pentacarbonyl in helium and the signals were recorded by the technique of laser magnetic reso nance. It is established that the molecule is linear in its ground sta te and that this state is (5) Delta in character; theoretical calculat ions suggest that it has gerade symmetry. The vibrational band origin is determined to be 1674.7195(4) cm(-1) and the rotational constant fo r the (0,0,0) level is 3.01328(3) cm(-1). This latter value correspond s to an r(0) Fe-H bond length of 0.1665 nm. (C) 1996 American Institut e of Physics.