Infrared Action Spectroscopy of Low-Temperature Neutral Gas-Phase Molecules of Arbitrary Structure.
We demonstrate a technique for IR action spectroscopy that enables measuring IR spectra in a background-free fashion for low-temperature neutral gas-phase molecules of arbitrary structure. The method is exemplified experimentally for N-methylacetamide molecules in the mid-IR spectral range of 1000-1800  cm^{-1}, utilizing the free electron laser FELIX. The technique involves the resonant absorption of multiple mid-IR photons, which induces molecular dissociation. The dissociation products are probed with 10.49 eV vacuum ultraviolet photons and analyzed with a mass spectrometer. We also demonstrate the capability of this method to record, with unprecedented ease, mid-IR spectra for the molecular associates, such as clusters and oligomers, present in a molecular beam. In this way the mass-selected spectra of low-temperature gas-phase dimers and trimers of N-methylacetamide are measured in the full amide I-III range.
Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden.|Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernoovield 7-c, 6525 ED Nijmegen, The Netherlands.
Vasyl
V
Yatsyna
Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernoovield 7-c, 6525 ED Nijmegen, The Netherlands.
Daniël J
DJ
Bakker
Department of Physics, Stockholm University, 106 91 Stockholm, Sweden.
Peter
P
Salén
Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden.
Raimund
R
Feifel
Radboud University, Institute for Molecules and Materials, FELIX Laboratory, Toernoovield 7-c, 6525 ED Nijmegen, The Netherlands.
Anouk M
AM
Rijs
Department of Physics, University of Gothenburg, 412 96 Gothenburg, Sweden.
Vitali
V
Zhaunerchyk