Di-iron and nickeliron

Abstract

Resonance Raman progressions assigned to Fe2 and NiFe isolated in solid Ar and Kr are reported. ωe″ and ωe″xe″ for the two molecules are found to be 299.6 and 1.4 cm−1 and 320.0 and 1.32 cm−1, respectively. In addition, an anti-Stokes progression of inordinate intensity was observed for Fe2. On the basis of a laser power study this was suggested to arise from consecutive two-photon absorption processes which are efficient in this case as a result of very long vibrational relaxation lifetimes of the excited vibrational states of the electronic ground state of Fe2. No spectrum of Fe2 was detected in either solid N2 or solid methane, supporting previous reports that Fe2 reacts with these substances to form complexes. With high resolution, each of the bands of the resonance Raman progression of Fe2 is observed to be a multiplet. Some of the multiplet structure results from the expected isotope effect but additional structure is seen because for a particular value of Δv″ there are transition with different initial values of v″.