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We have interfaced a newly constructed eleven chamber interferometer, the ETH-SLS Bruker IFS 125 HR prototype 2009, to the infrared port available at the Swiss Light Source (SLS), located at the Paul-Scherrer-Institute. The Maximum... more
We have interfaced a newly constructed eleven chamber interferometer, the ETH-SLS Bruker IFS 125 HR prototype 2009, to the infrared port available at the Swiss Light Source (SLS), located at the Paul-Scherrer-Institute. The Maximum Optical Path Difference (MOPD) of this spectrometer is 11.70 m allowing for a best theoretical unapodized resolution of 0.00053 cm-1 (18 MHz). The ETH-SLS Bruker spectrometer is a further development of our nine chamber interferometer Bruker IFS 120/125 Zurich prototype 2001 which has an MOPD of 9.4 m and unapodized resolution of 0.00068 cm-1 (23 MHz). We present spectra of CO and pyrimidine (C_4H_4N_2) as examples to illustrate the improved resolution. Due to the high brightness of the synchrotron source the signal-to-noise ratio is effectively 5 to 20 times better than that of conventional thermal sources in the spectral region between 180 and 900 cm-1 (6-28 THz). We present examples of pyrimidine (C_4H_4N_2) and CDBrClF spectra in the region 600 to 900 cm-1 and of phenol (C_6H_5OH) and aniline (C_6H_5NH_2) spectra in the region 180 to 350 cm-1. Due to the excellent resolution and the bright synchrotron source we were able to detect the spin statistical weights in the pyrimidine spectra and found new combination bands in the CDBrClF spectra. We were able to rotationally resolve the torsional c-type band of phenol with nu0a=309.1141 cm-1 and nu0b=309.5517 cm-1 and detect a torsional splitting of 0.4376 cm-1 in the v=1 torsional level. In addition, we were able to rotationally resolve and assign the very weak two torsional b-type subbands of aniline with nu0a=234.8 cm-1 and nu0b=304.3 cm-1 showing the mode selective inversion splitting. S. Albert, K.K. Albert and M. Quack, Trends in Optics and Photonics, 2003, 84, 177. S. Albert and M. Quack, ChemPhysChem, 2007, 8, 1271. S. Albert and M. Quack, J. Mol. Spectrosc., 2007, 243, 280. B. Fehrensen, M. Hippler and M. Quack, Chem. Phys. Lett., 1998, 298, 320.
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The Millimeter and Submillimeter Spectra of the Ground State and Excited \u3cem\u3e\u3csub\u3ev9\u3c/sub\u3e\u3c/em\u3e, \u3cem\u3e\u3csub\u3ev8\u3c/sub\u3e\u3c/em\u3e, \u3cem\u3e\u3csub\u3ev7\u3c/sub\u3e\u3c/em\u3e, and \u3cem\u3e\u3csub\u3ev6\u3c/sub\u3e\u3c/em\u3e Vibrational State of HNO\u3cs...more
The purpose of this note is to report in the literature the latest millimeter and submillimeter spectroscopic measurements and analyses for the rotational structure of a number of vibrational states of HNO3
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High-resolution rovibrational spectroscopy of fluorobenzene, C<sub>6</sub>H<sub>5</sub>F: analysis of the <i>B</i><sub>1</sub> fundamentals ν<sub>4</sub>, ν<sub>10<i>b</i></sub>, ν<sub>17<i>b</i></sub>, the <i>B</i><sub>2</sub> fundamental ν<sub>15</sub> and assignment of the <i>A</i><sub>1</sub>...more
Author Institution: Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110-2499; Physical Chemistry, ETH Zurich, CH-8093 Zurich, Switzerland
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The Doppler-limited FTIR spectrum of the band system in the region 1070-1170 cm-1 (Doppler width &ap; 0.0015 cm-1, FWHM) was measured with our new Bruker IFS 120 HR Zürich prototype (ZP2001) spectrometer. This instrument allows for an... more
The Doppler-limited FTIR spectrum of the band system in the region 1070-1170 cm-1 (Doppler width &ap; 0.0015 cm-1, FWHM) was measured with our new Bruker IFS 120 HR Zürich prototype (ZP2001) spectrometer. This instrument allows for an unapodized resolution of 0.0007 cm-1 (FWHM). This is the highest resolution realized so far by a commercial FTIR spectrometer system. It allows high-resolution analysis of the room temperature spectra of the strongly coupled modes nu 3(a') and nu 8(a''), corresponding to the symmetric and antisymmetric CF-stretching vibrations, including also further couplings not analysed previously. The present analysis is based on effective rotational Hamiltonians for the v3 = 1 and v8 = 1 states, including all terms up to sextic, and involves the full first-order Coriolis interaction operator TMPH1671ueq001 nu 9 and nu 6 + 2nu 9 levels with good accuracy. We describe possible approaches to the analysis. The final analysis involves both chlorine isotopomers and includes all hybrid components which are allowed by symmetry. It results in the band centres TMPH1671math003 nu 6+2nu 9)0 = 1144.32 cm-1, where the last digit is rounded, relating to the first digits differing in two types of analyses and data sets from our work. The main Coriolis interaction parameters are TMPH1671math006 cm-1 and TMPH1671math007 cm-1. In addition, smaller interactions could also be determined quantitatively. Our results are in essential agreement with the original analysis of Luckhaus and Quack (1989, Molec. Phys., 68, 745), which was, however, much less complete and precise. We discuss the comparison of different types of analyses and further recent results on this band system. We report ab initio calculations for this molecule on the MP2 level of theory with an aug-cc-pVDZ or an aug-cc-pVTZ basis set. Various subspaces of the potential energy and electric dipole moment hypersurface have been calculated in reduced normal coordinates including up to three dimensions. With these hypersurfaces we determined the corresponding vibrational absorption spectra, comprising transition wavenumbers and intensities. An analysis of the vibrational levels with an effective Hamiltonian was used to derive anharmonic constants. We also derived Coriolis coupling constants and integrated absorption intensities ab initio, which are compared with the present and previous experimental and theoretical results. The complete set of data as analysed is tabulated in Appendix A of this publication [61].
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The high-resolution gas phase Fourier transform infrared spectrum of the linear molecule isocyanogen, CNCN, has been measured in the 2000–2400 cm−1 region. The C≡N stretching band systems ν1 and ν2 located around 2302.0 and 2059.7 cm−1,... more
The high-resolution gas phase Fourier transform infrared spectrum of the linear molecule isocyanogen, CNCN, has been measured in the 2000–2400 cm−1 region. The C≡N stretching band systems ν1 and ν2 located around 2302.0 and 2059.7 cm−1, respectively, were observed with an unapodized resolution of 0.003 cm−1. In the analysis of these band systems hot bands originating from the states with up to 3 quanta of ν5, the singly excited ν4, and the combination state (ν4 ν5) = (11) were assigned. Effective spectroscopic constants of the numerous subbands as well as constants of an effective Hamiltonian are presented. An analysis of rotation–vibration interaction in CNCN as well as a complete valence force field are presented. The equilibrium rotational constant Be of CNCN was found to be 5172.66 (18) MHz, the diagonal valence force constants determined for C=N–C≡N are for the Σ modes (in aJ/Å2): fC=N− = 15.1, f=N−C≡ = 8.3, f−C=N = 17.1, and for the Π modes (in aJ): fC=N−C≡ = 0.141, f=N−C≡N = ...
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... meter spectroscopy technique offers gener-al analytical utility, speed, and detection capability. Sieghard Albert Douglas T. Petkie Ryan PA Bettens Sergei P. Belov Frank C. De Lucia Ohio State University Analytical Chemistry News... more
... meter spectroscopy technique offers gener-al analytical utility, speed, and detection capability. Sieghard Albert Douglas T. Petkie Ryan PA Bettens Sergei P. Belov Frank C. De Lucia Ohio State University Analytical Chemistry News & Features, November 1, 1998 719 A Page 2. ...
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{M. Quack, {\it Angew. Chem. Intl. Ed. Engl.{M. Quack, {\it Chem. Phys. Lett.{{\rm S. Albert, K.K. Albert, and M. Quack{K.K. Albert, S. Albert, M. Quack, J. Stohner O. Trapp and V. Schurig, {\it to be published{M. Quack and J. Stohner,... more
{M. Quack, {\it Angew. Chem. Intl. Ed. Engl.{M. Quack, {\it Chem. Phys. Lett.{{\rm S. Albert, K.K. Albert, and M. Quack{K.K. Albert, S. Albert, M. Quack, J. Stohner O. Trapp and V. Schurig, {\it to be published{M. Quack and J. Stohner, {\it Phys. Rev. Lett.
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S. Albert and M. Quack, \emph{ChemPhysChemH. R. Dubal and M. Quack, \emph{J. Chem. Phys.S. Albert, M. Winnewisser and B.P. Winnewisser, \emph{Ber. Bunsenges. Phys. Chem.S. Albert, K.K. Albert and M. Quack, \emph{Trends in Optics and... more
S. Albert and M. Quack, \emph{ChemPhysChemH. R. Dubal and M. Quack, \emph{J. Chem. Phys.S. Albert, M. Winnewisser and B.P. Winnewisser, \emph{Ber. Bunsenges. Phys. Chem.S. Albert, K.K. Albert and M. Quack, \emph{Trends in Optics and PhotonicsH.D. Bist, J. Brand and D.R. Willams, \emph{J. Mol. Spectrosc.M.L. Hause, Y.H. Yoon, A.S. Case and F. Crim, \emph{J.~Chem.~Phys.
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$^{a}$Thomas M. Goyette, Lee C. Oesterling, Douglas T. Petkie, Randy A. Booker, Paul Helminger, and Frank C. De Lucia, J. Mol. Spectrosc. 175, 395-410 (1996).
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Author Institution: Justus-Liebig-Universität Giessen, 35392 Giessen, Germany.Fulminic acid belongs to the class of quasilinear molecules. Precise ab initio methods are not available to reproduce the quasilinear behavior of the molecule.... more
Author Institution: Justus-Liebig-Universität Giessen, 35392 Giessen, Germany.Fulminic acid belongs to the class of quasilinear molecules. Precise ab initio methods are not available to reproduce the quasilinear behavior of the molecule. In particular, the calculations cannot predict the multitude of accidental resonance interactions. We have now analyzed the infrared spectra of HCNO and its isotopomers $H^{13}CNO$ and $H^{13}C^{15}NO$ up to $7000 cm^{-1}$. More then 30000 lines could be assigned. The low symmetry of the molecule and the anharmonic quasilinear bending mode lead to an extraordinarily rich array of interactions. Most of the interactions could be classified into a network of resonance systems. As a result of such classifications, it has been possible to identify dark states. An overview and comparison of the different network in HCNO, $H^{13}CNO$ and $H^{13}C^{15}NO$ will be discussed. The term value schemes built up with the help of the Ritz combination principle will be presented
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In our group we pursue two experimental approaches to investigate Intramolecular Vibrational Redistribution (IVR)^a: this process can be studied by time-resolved femtosecond pump-probe experiments, or the corresponding time-dependent... more
In our group we pursue two experimental approaches to investigate Intramolecular Vibrational Redistribution (IVR)^a: this process can be studied by time-resolved femtosecond pump-probe experiments, or the corresponding time-dependent quantum dynamics can be obtained from stationary spectra in the IR at high frequency resolution by a time-dependent analysis using the underlying Hamiltonian and time evolution operator. Recent work in our group
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ABSTRACT The infrared spectrum of the chiral molecule CDBrClF has been measured with a resolution of 0.001 cm-1 and analysed in the ν5, ν4, ν3 and 2ν4 regions. The results are discussed in relation to molecular parity violation.
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Today, the vast majority of electron storage rings delivering synchrotron radiation for general user operation offer a dedicated infrared port. There is growing interest expressed by various scientific communities to exploit the mid-IR... more
Today, the vast majority of electron storage rings delivering synchrotron radiation for general user operation offer a dedicated infrared port. There is growing interest expressed by various scientific communities to exploit the mid-IR emission in microspectroscopy, as well as the far infrared (also called THz) range for spectroscopy. Compared with a thermal (laboratory-based source), IR synchrotron radiation sources offer enhanced brilliance of about two to three orders of magnitude in the mid-IR energy range, and enhanced flux and brilliance in the far-IR energy range. Synchrotron radiation also has a unique combination of a broad wavelength band together with a well defined time structure. Thermal sources (globar, mercury filament) have excellent stability. Because the sampling rate of a typical IR Fourier-transform spectroscopy experiment is in the kHz range (depending on the bandwidth of the detector), instabilities of various origins present in synchrotron radiation sources pl...
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Page 1. JOURNAL OF MOLECULAR SPECTROSCOPY 167, 375-382 ( 1994) Fourier Transform Spectra of Overtone Bands of HCN from 4800 to 9600 cm&quot;1 : Some New Transitions of Bending Combination Modes Wolfgang Quapp,* Stefan Klee,! Georg Ch.... more
Page 1. JOURNAL OF MOLECULAR SPECTROSCOPY 167, 375-382 ( 1994) Fourier Transform Spectra of Overtone Bands of HCN from 4800 to 9600 cm&quot;1 : Some New Transitions of Bending Combination Modes Wolfgang Quapp,* Stefan Klee,! Georg Ch. Mellau,! ...
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High-resolution rovibrational spectroscopy of fluorobenzene, C<sub>6</sub>H<sub>5</sub>F: analysis of the <i>B</i><sub>1</sub> fundamentals ν<sub>4</sub>, ν<sub>10<i>b</i></sub>, ν<sub>17<i>b</i></sub>, the <i>B</i><sub>2</sub> fundamental ν<sub>15</sub> and assignment of the <i>A</i><sub>1</sub>...more
<div><p>We report the rovibrational analysis of the highly resolved (instrumental bandwidth = 0.0008–0.0018 cm<sup>−1</sup> full width at half maximum [FWHM]) Fourier transform infrared (FTIR) spectrum of... more
<div><p>We report the rovibrational analysis of the highly resolved (instrumental bandwidth = 0.0008–0.0018 cm<sup>−1</sup> full width at half maximum [FWHM]) Fourier transform infrared (FTIR) spectrum of fluorobenzene measured with our Zurich Fourier transform interferometric spectrometer prototype (Bruker IFS 125 HR ZP 2001) in the range 600–1300 cm<sup>−1</sup>. The analysis comprised initially three <i>B</i><sub>1</sub> bands and led to an identification of Coriolis resonances and a new assignment of three <i>A</i><sub>1</sub> bands in the region 790–850 cm<sup>−1</sup>. In detail, three <i>B</i><sub>1</sub> fundamentals, ν<sub>4</sub> ( cm<sup>−1</sup>), ν<sub>10<i>b</i></sub> ( cm<sup>−1</sup>) and ν<sub>17<i>b</i></sub> ( cm<sup>−1</sup>) have been analysed using an effective Hamiltonian. A perturbation of the <i>B</i><sub>2</sub> fundamental ν<sub>15</sub> ( cm<sup>−1</sup>) was detected and the interaction is interpreted as a crossing Coriolis resonance between the states ν<sub>15</sub> and a dark state assigned as ν<sub>4</sub> + ν<sub>18<i>b</i></sub>. The Coriolis parameter ξ<sub><i>x</i></sub> was determined to be −0.00345 cm<sup>−1</sup>. The rovibrational analysis of the region between 790 and 850 cm<sup>−1</sup> revealed three <i>A</i><sub>1</sub> bands assigned to ν<sub>12</sub> ( cm<sup>−1</sup>), 2ν<sub>18<i>b</i></sub> ( cm<sup>−1</sup>) and 2ν<sub>16<i>a</i></sub> ( cm<sup>−1</sup>). A Coriolis resonance between the states 2ν<sub>16<i>a</i></sub> and a dark state assigned as ν<sub>10<i>a</i></sub> ( cm<sup>−1</sup>, <i>A</i><sub>2</sub> symmetry) was identified and the Coriolis coupling constant ξ<sub><i>z</i></sub> was determined to be 0.0145 cm<sup>−1</sup>. The root mean square deviation <i>d</i><sub>rms</sub> is in the range 0.0002 − 0.0003 cm<sup>−1</sup> (6–9 MHz) for the adjustment of the model to almost 17000 assigned rovibrational absorption line positions. This indicates an excellent representation of the data by the model.</p></div
Research Interests: Engineering, Physics, Biophysics, Chemistry, Biotechnology, and 10 morePlant Biology, Cell Biology, HR, Biological Sciences, FTIR, IFS, Bands, CM, B, and FWHM
Author Institution: Physical Chemistry, ETH Zurich, CH-8093 Zurich, SwitzerlandA complete understanding of the absorption behavior of the Earth's atmosphere and of the atmospheres of the giant planets (Saturn and Jupiter) and their... more
Author Institution: Physical Chemistry, ETH Zurich, CH-8093 Zurich, SwitzerlandA complete understanding of the absorption behavior of the Earth's atmosphere and of the atmospheres of the giant planets (Saturn and Jupiter) and their moons (Titan) requires a detailed spectroscopic investigation of methanoid molecules over full atmospheric temperature ranges. For that reason we have interfaced a collisional and enclosive cooling cell} in press.} based on White-type multireflection optics to our FTIR IFS125 HR prototype 2001 spectrometer}, {\it Trends in Optics and Photonics} {\bf 84}, 177 (2003).} (MOPD=10 m). This cell makes it possible to record spectra at high spectral resolution in the temperature range 4-400 K with absorption path lengths up to 20 m. We have recorded the spectra of CH$_4$} and its isotopomers} and of CHF$_3$}, CHClF$_2$} {\bf 102}, 1671 (2004).} and CHCl$_2$F$^a$ between 2000 and 6000 cm$^{-1}$ in the temperature range 60-300 K. The spectra were recorded at resolutions ranging from 0.0015 to 0.004 cm$^{-1}$. We will present an analysis of the spectra of CHCl$_2$F in the $2\nu_3$ and $3\nu_3$ regions and an initial assignment of the resonance system $2\nu_3/\nu_3 +\nu_8/2\nu_8$ of CHClF$_2$. We discuss coincidences with CO$_2$ laser lines in the $2\nu_3$ region of the isotopic chiral molecule CH$^{35}$Cl$^{37}$ClF. Doppler-free quasi-resonantly enhanced ultra-high two-photon absorption experiments may be carried out in this region to study parity violation} {\bf 114}, 4812 (2002), M. Quack and J. Stohner, {\it J. Chem. Phys.} {\bf 119}, 11228 (2003), R. Berger, G. Laubender, M. Quack, A. Sieben, J. Stohner and M. Willeke, {\it Angew. Chem. Int. Ed. Eng.} {\bf 44}, 3623 (2005).} in this molecule. In addition, we show CO nanoparticles recorded at 6 K } {\bf 72}, 3946 (2001).}
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We introduce the concept of a molecular quantum switch and demonstrate it with the example of meta-d-phenol, based on recent theoretical and high-resolution spectroscopic results for this molecule. We show that in the regime of tunneling... more
We introduce the concept of a molecular quantum switch and demonstrate it with the example of meta-d-phenol, based on recent theoretical and high-resolution spectroscopic results for this molecule. We show that in the regime of tunneling switching with localized low-energy states and delocalized high-energy states the molecular quantum switch can be operated in two different ways: (i) a quasiclassical switching by coherent infrared radiation between the two isomeric structures syn- and anti-m-d-phenol; and (ii) a highly nonclassical switching making use of bistructural quantum superposition states of the syn and anti structures, which can be observed by their time-dependent spectra after preparation.
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$^{a}$ J. Mol. Spectresc., 56, 449-470(1975) $^{b}$ J. Mol. Spectrosc., 142, 29-56 (1990) $^{c}$ J. Mol. Spectrosc., 74, 9-25 (1979)
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We have carried out new measurements of infrared spectra of the spherical top molecules 12CH4, 13CH4 and 12CD4 at low – (80K) and room temperature (298K). Spectra were recorded at very high resolution (0.0027 cm−1 around 2900 cm−1) using... more
We have carried out new measurements of infrared spectra of the spherical top molecules 12CH4, 13CH4 and 12CD4 at low – (80K) and room temperature (298K). Spectra were recorded at very high resolution (0.0027 cm−1 around 2900 cm−1) using the Z¨urich prototype Bruker 125 spectrometer (ZP 2001)3 combined with a low temperature cooling cell. Due to low temperature, the Doppler full width at half maximum (0.0045 cm−1 around 2900 cm−1 at 80K) was reduced by a factor of 1.91. We report the analysis of two low – and six room temperature spectra and present the global analysis of 4000 (2000 newly assigned) 13CH4-transitions from 0 up to 3200 cm−1. The results are compared to previous work. In the present work line positions are reproduced with an rms deviation of 0.0009 cm−1. The complex interacting system is analyzed using an effective Hamiltonian. This tensorial formalism is discussed conceptually as well.
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A new FAst Scan Submillimeter Spectroscopic Technique (FASSST) is described. It uses voltage tunable Backward Wave Oscillators (BWOs) as primary sources of radiation. In contrast to the more traditional phase or frequency lock techniques,... more
A new FAst Scan Submillimeter Spectroscopic Technique (FASSST) is described. It uses voltage tunable Backward Wave Oscillators (BWOs) as primary sources of radiation. In contrast to the more traditional phase or frequency lock techniques, it uses fast scan (approximately 105 Doppler limited resolution elements/sec) and optical calibration methods. Its attributes include (1) absolute frequency calibration to approximately 1/10 of a Doppler limited linewidth (less than 0.1 MHz), (2) high sensitivity, (3) the ability to measure many thousands of lines/sec, and (4) simplicity. This system is made possible by (1) the excellent short term spectral purity of the broadly (approximately 100 GHz) tunable BWOs, (2) a very low noise, rapidly scannable high voltage power supply, (3) fast data acquisition, and (4) software capable of automated calibration and spectral line measurement.
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Dimethyl ether (CH3OCH3) is a well-known interstellar molecule with a large abundance in hot core regions. We have measured many rotational-torsional transition lines of this molecule in the 100-550 GHz frequency range using two... more
Dimethyl ether (CH3OCH3) is a well-known interstellar molecule with a large abundance in hot core regions. We have measured many rotational-torsional transition lines of this molecule in the 100-550 GHz frequency range using two experimental techniques: a klystron-based traditional millimeter-wave spectrometer and a new fast scan spectrometer (designated "FASSST") with a voltage-tunable backward wave oscillator. The lines arising from the ground vibrational state have been combined with previous data, mainly at lower frequencies, to form a global data set consisting of over 1600 lines that have been assigned and fitted by an effective Hamiltonian method. The spectral constants obtained from the fit allow us to predict the frequencies of almost 6000 additional lines of dimethyl ether through 600 GHz.
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ABSTRACT With the long-term aim of understanding the detailed mechanism of intramolecular vibrational redistribution (IVR) from the CH-stretching mode to the low-frequency modes of the heavy atom framework, we have studied the infrared... more
ABSTRACT With the long-term aim of understanding the detailed mechanism of intramolecular vibrational redistribution (IVR) from the CH-stretching mode to the low-frequency modes of the heavy atom framework, we have studied the infrared spectrum of CHD2I below 3100 cm and around 6000 cm using high-resolution Fourier transform infrared spectroscopy. A detailed analysis of the ν1 fundamental based on 1349 assigned transitions results in an accurate band centre cm and further spectroscopic parameters are summarised in Table 3. Numerous local perturbations are observed in the analysis. The results are discussed in relation to previous spectroscopic work on this molecule and to IVR processes observed previously by fs pump-probe spectroscopy in our group.