Mid-infrared spectroscopy of molecular ions in helium nanodroplets

Abstract

Vibrational energy relaxation of benzene dimer and trimer in the CH stretching region studied by picosecond time-resolved IR-UV pump-probe spectroscopy J. Chem. Phys. 136, 044304 (2012) Influence of the cluster dimensionality on the binding behavior of CO and O2 on Au13 J. Chem. Phys. 136, 024312 (2012) Core-to-Rydberg band shift and broadening of hydrogen bonded ammonia clusters studied with nitrogen K-edge excitation spectroscopy J. Chem. Phys. 136, 014308 (2012) Theoretical characterization of intermolecular vibrational states through the multi-configuration time dependent Hartree approach: The He2,3ICl clusters J. Chem. Phys. 135, 244309 (2011) Studies on the structure, stability, and spectral signatures of hydride ion-water clusters J. Chem. Phys. 135, 214308 (2011) Additional information on J. Chem. Phys. High resolution IR spectra of aniline, styrene, and 1,1-diphenylethylene cations embedded in superfluid helium nanodroplets have been recorded in the 300-1700 cm −1 range using a free-electron laser as radiation source. Comparison of the spectra with available gas phase data reveals that the helium environment induces no significant matrix shift nor leads to an observable line broadening of the resonances. In addition, the IR spectra have provided new and improved vibrational transition frequencies for the cations investigated, as well as for neutral aniline and styrene. Indications have been found that the ions desolvate from the droplets after excitation by a non-evaporative process in which they are ejected from the helium droplets. The kinetic energy of the ejected ions is found to be ion specific and to depend only weakly on the excitation energy.

Ion formation upon electron collisions with valine embedded in helium nanodroplets

“…Clustering occurs in our experiments when valine molecules are embedded in superfluid helium nanodroplets at the extremely low temperature of 0.37 K [19]. Few studies on biomolecules embedded in helium nanodroplets have been carried out so far [20][21][22][23][24][25][26]. Noteworthy is a successful experiment in which a protein ion with a mass of 12 000 u was embedded in a droplet [27].…”

Source of slow lithium atoms from Ne or H2 matrix isolation sublimation

“…Besides superfluid helium droplets, [6][7][8][9] neon, [10][11][12] and parahydrogen matrices 2, [13][14][15] have been among the most interesting host materials. Because of their light mass the zero point energy becomes more relevant.…”

Photoionisaton of pure and doped helium nanodroplets

“…Moreover, it was found that the effect of the He environment on the absorption spectra, in terms of matrix shift and line broadening, is quite similar for ions and neutrals despite the fact that ions interact much more strongly with He than neutrals. Thus, infrared and also optical excitation of molecular ions detected by the ejection of the ions from the He droplets provides a novel, highly sensitive spectroscopic method for cold molecular ions [145].…”