Laser-Stark and Fouriertransform spectroscopy of the nu 3 band of monodeuterated fromic acid, HCOOD (original) (raw)
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Laser-Stark and Fourier-transform spectroscopy of the ν_3 band of monodeuterated formic acid, HCOOD
Journal of the Optical Society of America B, 1987
The 3 fundamental band of monodeuterated formic acid, HCOOD, at 5.64 um has been studied by using a combination of CO-laser-Stark spectroscopy and high-resolution Fourier-transform spectroscopy. The analysis of the Fourier-transform data, together with all previous pure rotational ground-state data, gave precise values for the V 3-band origin and rotational and centrifugal distortion parameters. Slightly refined ground-state parameters were also obtained. A c-type Coriolis interaction between V3 and 6 + 7 was included in the analysis, resulting in a value for the interaction parameter and for some effective parameters of the perturbing state. A second weaker Coriolis interaction between 3 and v 5 + P was noted but not analyzed. The Stark data yielded precise values for the Ma and Mb dipole-moment components in the ground and excited states. off mode using any one of the 2 C160, 3 C 1 60, 2 C180, or 13 C18O isotopes. Brewster-angle windows on the laser and Stark cell may be rotated to give either parallel or perpendicular orientation of the laser radiation relative to the Stark field, yielding AM = 0 or i1 selection rules, respectively. The HCOOD sample pressure was typically about 5 mTorr, and electric fields of up to 40 kV/cm were employed. The zero-field absorption spectrum of HCOOD was recorded using a Bomem Model DA3.002 FT spectrometer operating at its maximum resolution of 0.0036 cm-' (apodized). The absorption path was 12 cm, and the sample pressure about 0.2 mTorr. The spectrometer was fitted with a CaF2 beam splitter and a liquid-He-cooled Ge:Cu detector. Absolute frequency calibration was made using H2O lines that appeared in the spectrum because of residual water vapor in the HCOOD sample. Their positions have recently been determined precisely by Brown and Toth." Formic-acid-OD samples (98% isotopic purity) were obtained from MSD Isotopes Ltd. In both the FT and the laser-Stark experiments, we encountered difficulties because of rapid isotopic exchange in the absorption cells,
He I photoelectron spectroscopy of four isotopologues of formic acid: HCOOH, HCOOD, DCOOH and DCOOD
Chemical Physics, 2003
He I photoelectron spectra of four isotopologues of formic acid, HCOOH, HCOOD, DCOOH and DCOOD have been measured, mainly with an electron kinetic energy resolution of 15 meV. Quantum chemical calculations of geometries, vibrational mode frequencies and the potential energy distributions characterising each normal mode were made for the neutral 1 1 A 0 ground state, the cation ground state 1 2 A 0 and first excited ion state 1 2 A 00 of the four isotopologues. The results were used to analyse observed vibronic structure in the two PES bands in the 11.3-13.5 eV energy region and this analysis provided values for several vibrational mode frequencies of the ion states. The calculated structure and internal dynamics of the 1 2 A 0 ground state of the ion provide satisfactory agreement with experiment but for the 1 2 A 00 excited state a more refined theoretical treatment, permitting greater structural flexibility, is required. The PES first ionization energy of HCOOH agrees well with that obtained from Rydberg series in absorption spectra, and values more precise than hitherto were obtained for the first and second ionization energies of the four isotopologues. Analysis is also made of PES features concerning the higher energy states of the ions between 12.2 and 21 eV. The adabatic ionization energies of the 2 2 A 0 , 2 2 A 00 , 3 2 A 0 and 4 2 A 0 states in this energy region were determined. Vibrational frequencies were obtained for the 3 2 A 0 ion state of the isotopologues and new assignments were made concerning the energy and structure of the 4 2 A 0 ion state, whose adiabatic energy was found to lie about 60 meV below the 3 2 A 0 state.
FTIR spectra of the ν 6 and ν 8 bands of 13C formic acid molecule—Assignment of FIR-laser lines
Journal of Molecular Spectroscopy, 2008
Two interacting vibrational modes m 6 and m 8 of 13 C species of formic acid have been studied with high resolution FTIR spectroscopy in the range 900-1300 cm À1 with an instrumental resolution of 0.0018 cm À1 . More than 10 000 lines have been assigned and fitted with a RMS deviation of 0.00024 cm À1 . The band centers, as well as the rotational, quartic and sextic centrifugal distortion parameters and 6 interaction parameters have been determined. The obtained parameters have enabled the assignments of 24 FIR laser emissions of this molecule observed previously by Dangoisse and Glorieux [D. Dangoisse, P. Glorieux, J. Mol. Spectrosc. 92 (1982) 283-297], Luis et al.
The FT-IR Spectrum of H13C15NO in the ranges 1800–3600 and 6300–7000cm−1
Journal of Molecular Structure, 2001
The midinfrared spectrum of H 13 C 15 NO, an isotopically substituted species of fulminic acid, has been analyzed in the ranges 1800±3600 and 6300±7000 cm 21 . More than 9000 infrared lines have been assigned, which makes it possible to identify more than 80 new vibrational levels. Power series constants of these levels are given. Each vibrational level with its rotational levels is globally or locally perturbed. Most of the interactions are part of resonance systems. Three resonance systems of H 13 C 15 NO (00105/01011, 10003 and 10011) are presented, as well as a comparison with the corresponding resonance systems of HCNO and H 13 CNO. In addition, an analysis of the 2n 1 band system and a comparison of the basic Coriolis-type resonances v 1 v 2 v 3 02=v 1 v 2 v 3 10 and Fermi-type resonances v 1 v 2 v 3 v 4 0=v 1 v 2 v 3 2 1v 4 4 are discussed for the three isotopomers HCNO, H 13 CNO and H 13 C 15 NO. q Fig. 12. Overview spectrum of the 2n 1 band system of H 13 C 15 NO. The regions between 6290 and 6330 cm 21 and between 6570 and 6970 cm 21 are expanded.
FTIR and millimeter wave investigation of the 7 1 and 9 1 states of formic acid HCOOH and H 13COOH
Journal of Molecular Spectroscopy, 2006
High resolution FTIR spectra of the two overlapping bands m 7 and m 9 of the 13 C species of formic acid have been measured and analyzed. Rotational transitions in the millimeter wave region were measured and included in the analysis. As in the parent species, there is a strong Coriolis interaction between the 7 1 and 9 1 states. The corresponding IR bands of the parent species have been remeasured and new MMW transitions recorded. The analysis of the spectra for the two species provides an opportunity to consider a reduction of the Hamiltonian employed for the analysis of this type of interacting system of states. Parameters with low correlations could be obtained. Several interstellar features coincide with transitions predicted from these parameters.
The far infrared spectrum of trans-formic acid: An extension up to 175cm−1
Journal of Quantitative Spectroscopy and Radiative Transfer, 2012
The far infrared spectrum of HCOOH was recorded at a high resolution (0.0009 cm À 1 ) and long path length (72 m) at the far-infrared beamline, Canadian Light Source. Spectra were recorded in the region 62-300 cm À 1 , showing transitions from the trans-isomer.
Overtone spectroscopy of formic acid
Chemical Physics, 2002
Vibrational assignments of fundamental, combination and overtone bands in the main isotopomer of gaseous transformic acid are reported from spectra either newly or previously [J. Chem. Phys. 113 (2000) 1535] recorded using highresolution Fourier transform and intracavity laser absorption spectroscopies. A total of 62 bands, with 32 newly reported ones, are observed from the lowest energy band, m 7 at 626.16 cm À1 up to 4m 1 at 13284.1 cm À1 . Among these bands, 43 are firmly assigned, and 16 tentatively. Effective vibrational constants are obtained. The normal modes of vibrations are further characterised using ab initio calculations providing fundamental band intensities and picturing normal mode nuclear displacements. The effective investigation of the rotational structure in the first CH stretch overtone band ð2m 2 Þ and in the second OH stretch overtone band ð3m 1 Þ is detailed. Rotational information is also presented for 3m 2 and two close-lying bands, that could be extracted from the strong overlapping formic acid dimer bands using artificial filtering procedures. Ó
The Astrophysical Journal, 1987
Laboratory observations of the pure rotational spectrum of Hco+ in its lowest excited bending state (v 1 , vL v 3)_= (0,1\0) are reported. Because of their severe excitation requirements, such vibrational satellites and the high-J ground-state lines also measured here sample only hot, dense regions of matter in active ~o~ec~ar cl~m? cores and circumstellar envelopes. As the Hco+ abundance is tied directly to the gas fractional wmzatw~, 1t 1s probable that the vib~ationally excited formyl ion transitions will provide high-contrast observatiOns of shocked ~olecular ma~en~, rather than the more quiescent, radiatively heated gas surrounding stellar sources detected With the few v1brat1onally excited neutral species observed to date.
Journal of Molecular Spectroscopy, 2010
The absorption spectra of trans and cis conformers of deuterated formic acid (HCOOD) isolated in argon and neon matrices are analyzed in the mid-infrared and near-infrared spectral regions (7900-450 cm À1 ). Vibrational excitation by narrow-band IR radiation is used to convert the lower-energy trans conformer to the higher-energy cis form. A large number of overtone and combination bands are identified. The results of anharmonic vibrational calculations (CC-VSCF) for both conformers are reported and compared to the experimental spectra.