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Title: Fully automated dual-frequency three-pulse-echo 2DIR spectrometer accessing spectral range from 800 to 4000 wavenumbers

A novel dual-frequency two-dimensional infrared instrument is designed and built that permits three-pulse heterodyned echo measurements of any cross-peak within a spectral range from 800 to 4000 cm{sup −1} to be performed in a fully automated fashion. The superior sensitivity of the instrument is achieved by a combination of spectral interferometry, phase cycling, and closed-loop phase stabilization accurate to ∼70 as. The anharmonicity of smaller than 10{sup −4} cm{sup −1} was recorded for strong carbonyl stretching modes using 800 laser shot accumulations. The novel design of the phase stabilization scheme permits tuning polarizations of the mid-infrared (m-IR) pulses, thus supporting measurements of the angles between vibrational transition dipoles. The automatic frequency tuning is achieved by implementing beam direction stabilization schemes for each m-IR beam, providing better than 50 μrad beam stability, and novel scheme for setting the phase-matching geometry for the m-IR beams at the sample. The errors in the cross-peak amplitudes associated with imperfect phase matching conditions and alignment are found to be at the level of 20%. The instrument can be used by non-specialists in ultrafast spectroscopy.
Authors:
; ; ; ; ; ; ; ; ;  [1] ;  [2]
  1. Department of Chemistry, Tulane University, New Orleans, Louisiana 70118 (United States)
  2. Institute for Nuclear Research of the Russian Academy of Sciences, Moscow 117312 (Russian Federation)
Publication Date:
OSTI Identifier:
22314652
Resource Type:
Journal Article
Resource Relation:
Journal Name: Review of Scientific Instruments; Journal Volume: 85; Journal Issue: 8; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ALIGNMENT; AMPLITUDES; BEAMS; DESIGN; DIPOLES; ERRORS; GEOMETRY; INFRARED SPECTRA; INFRARED SPECTROMETERS; INTERFEROMETRY; PEAKS; POLARIZATION; PULSES; SENSITIVITY; SPECTROSCOPY; STABILIZATION