Resonance Raman Spectroscopy of Mass Selected Chromium Trimers in an Argon Matrix

Abstract

The resonance Raman spectra of mass-selected chromium trimers (Cr 3 ) in argon matrixes have been obtained. Five resonance Raman transitions were observed between 450 and 690 nm. Four of them are assigned to a totally symmetric (a 1 ′) vibrational progression, from which we obtain a ground-state harmonic frequency of ω e ) 432.2 cm -1 with ω e x e ) 16.3 cm -1 . The other Raman line, observed at 302.0 cm -1 , is assigned to the degenerate bending motion V 2 (e′) of the triatomic metal cluster. The geometry of the ground state is that of an equilateral triangle (D 3h ). These results provide a value of the stretching force constant of k e ) 1.91 mdyne/Å and a spectroscopic atomization energy of 0.36 eV.

Metal Cluster Models for Heterogeneous Catalysis: A Matrix‐Isolation Perspective

“…Transition metal trimers have been generated in matrices for Sc, Zr, Hf, Nb, Ta, Cr, Mo, Mn, Fe, Ru, Co, Rh, (possibly Ir), Ni, Cu, Ag, and Au . Except for Sc, Mn, Co, Ni, and Ir, matrices with mass selected clusters have been generated.…”

“…Transitionm etal trimers have been generated in matrices for Sc, Zr,H f, Nb, Ta,C r, Mo, Mn, Fe, Ru, Co, Rh, (possibly Ir), Ni, Cu, Ag, and Au. [153,165,167,171,174,176,186,189,191,195,196,198,201,202,204,[206][207][208][209][210][211][212][213][214][215][216][217][218][219][220][221][222][223][224] Except for Sc, Mn, Co, Ni, and Ir,m atrices with mass selected clusters have been generated. The clusters have been identified by resonance Ramans pectra, UV/Vis absorptions, ESR spectra,o rf luorescence.…”

“…Reactions of metal clusters have been studied with O 2 , N 2 , CO, N 2 O and H 2 O . There are only a few examples for reactions of clusters with organic molecules …”

Photoinduced molecular dissociation and photoinduced recombination mediated by superfluid helium nanodroplets

“…Keeping possible fragmentation in mind, the comparison allows an assignment of the Cr 2 + y 5 P 3 a 5 S 2 signal ( Fig. [50][51][52] The detection of Cr 3 + and Cr 4 + therefore suggests that the Cr 2 dissociation process and surface migration of one atom is not disturbed by the presence of a further Cr atom or dimer in the droplet. We mention that in addition to the Cr + Cr + -Cr 2 + recombination, another recombination path is possible, although unlikely.…”

“…For the strongly bound Cr 2 singlet ground state (binding energy = 1.42 eV (11 450 cm À1 ) 38 ), the majority of droplets are expected to survive the formation for a size distribution maximum of N = 6300 and an energy of 5 cm À1 dissipated per evaporated He atom. 40,51,52,55,56 41,43,54 Cr 2 excitation spectra in other solid rare gas matrices yield usually shifted and broadened spectral features, but cannot provide a consistent picture about the magnitude of the shift.…”