Lowest Overtone and Combination Levels of DCCI: The Fermi Resonance v3 = 1/v5 = 2.
The infrared spectrum of deuterated monoiodoacetylene DCCI in the region of 220-550 cm-1 has been studied at a resolution of 0.0020 cm-1. The hot bands nu3 <-- nu15 and 2nu0,25 <-- nu15 have been analyzed by considering especially the Fermi resonance v3 = 1/v5 = 2. In the next layer of the hot bands (nu3 + nu5)1 <-- nu3, (nu3 + nu5)1 <-- 2nu0,25 and 3nu1,35 <-- 2nu25 the same Fermi resonance appears between v3 = v5 = 1 and v5 = 3. In addition, various l resonances at the overtone levels have been considered. As a result, the vibrational and rotational constants for the level systems v3 = 1/v5 = 2 and v3 = v5 = 1/v5 = 3 together with the resonance parameters have been obtained. Copyright 1999 Academic Press.
High-Resolution FTIR and Photoacoustic Overtone Spectrum of HCCI
The first and second C-H overtone vibration-rotation absorption spectra of monoiodoacetylene (HCCI) have been recorded using an FTIR spectrometer with an instrument resolution of about 0.005 cm-1 (0.9/MOPD). The third overtone spectrum has been obtained using a titanium:sapphire ring laser spectrometer with a spectral resolution of about 0.02 cm-1. Due to anharmonic resonances like Fermi and Darling-Dennison resonances, accompanying bands can be observed close to the main overtone band. All the observed bands have been rotationally analyzed. Published vibrational data together with present results are used in a model which includes anharmonic resonances. Vibrational assignments of the observed bands are based on this calculation. The agreement between calculated and observed energy levels is good considering the amount of data available. Copyright 1997 Academic Press. Copyright 1997Academic Press
A Microwave Fourier Transform Spectrometer in the Frequency Band From 26 to 40 GHz
We report the design and performance of a microwave Fourier transform spectrometer in the frequency region between 26 and 40 GHz for the investigation of rotational spectra. The performance is illustrated by rotational transitions of allene and allene-d4 molecules with a very small dipole moment in vibrational excited states. The sensivity and Doppler limited linewidth is demonstrated by measurements of transitions of isotopomers of carbonyl sulfide and sulfur dioxide.