The vibrational energy levels of small transient molecules isolated in neon and argon matrices

Abstract

Shifts in the ground-state vibrational fundamental frequencies of diatomic and small polyatomic free radicals, molecular ions, and other short-lived molecules upon trapping in neon and argon matrices are reviewed, with extensive documentation. Recent experimental and theoretical papers concerned with matrix shift phenomena are also discussed. The vibrational fundamentals of most molecules appear at somewhat lower frequencies in an argon matrix than in a neon matrix. Distributions of the matrix shifts have been obtained for stretching, hydrogen-stretching, and bending fundamentals. Neon-matrix shifts are typically smaller than argon-matrix shifts. There is a slight tendency for stretching vibrations observed in an argon matrix to lie below the gas-phase band centers.

Equilibrium Structure and Fundamental Vibrational Wavenumbers in Difluorosilanone: An ab Initio Study

“…Such large discrepancies indicate strongly that m 3 and 2 m 3 have not been assigned correctly in the experimental work [1], even if we take into account that the experimental vibrational wavenumbers have been measured in an argon matrix and not in the gas phase. Argon-matrix shifts in bending fundamental wavenumbers are almost certainly not larger than 2% in absolute value [28], which amounts to about 9 cm ±1 in the case of m 3 . Therefore, such matrix shifts cannot explain the large discrepancies for m 3 and 2 m 3 (see above).…”

Superfluid Helium Droplets: A Uniquely Cold Nanomatrix for Molecules and Molecular Complexes

“…Thus matrix isolation provides a versatile tool to study a wide variety of these transient species. [2][3][4][5] Usually it is possible to obtain a rather large optical density of isolated species and maintain them for long times of several hours and even days which facilitates the straightforward application of the Fourier transform infrared and other optical spectroscopic techniques, such as Raman scattering. The relatively strong interaction with the matrix surrounding, which, on the one hand, localizes the solute species and provides stability within the matrix, often results, however, in considerable inhomogeneous broadening of the spectral lines owing to the number of different sites which the solute molecules can occupy.…”

On observing C60+and C602+in laboratory and space

“…IR frequencies of C 60 , C + 60 , and C − 60 absorptions in Ne and Ar matrixes are presented in Table 1 together with Ne data for C so far, we estimate the low-temperature gas-phase absorption frequencies from the matrix data. It is known, that Gas-Ne matrix IR frequency shifts are in general smaller than Gas-Ar shifts (Jacox 1994). The primary reason is the lower polarizability of solid Ne and hence the weaker interaction of an oscillating dipole with its environment.…”