High-resolution absorption lineshapes of the R(7) and P(2) transitions in the first overtone (v = 0-2) band of H(79)Br have been recorded at room temperature using a pair of distributed feedback diode lasers operating near 1.95 and 2.00 µm, respectively. Spectral line intensities and self-broadening coefficients were determined by fitting the measured spectra (for various pressures P = 10-100 Torr) with Voigt profiles and compared with values in the literature. Measured line intensities for the P(2) and R(7) transitions are approximately 11 and 16% higher than those listed in the HITRAN database, respectively. The measured self-broadening coefficient of the P(2) transition is approximately 14% lower than the value listed in HITRAN. Measurements of the P(2) lineshapes at low pressure (100 mTorr) were modeled with eight-line Gaussian profiles based on ground state (v = 0) hyperfine constants to include the effects of nuclear electric quadrupole interactions. Copyright 2000 Academic Press.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1006/jmsp.1999.8038 | DOI Listing |
Spectrochim Acta A Mol Biomol Spectrosc
December 2024
Department of Physics and Engineering, Albany State University, GA 31707. USA. Electronic address:
This work represents a comprehensive study of the ground vibrational state of C-13 substituted methanol using very high-resolution far-infrared (FIR) and infrared (IR) Synchrotron Radiation spectra recorded with a very high signal-to-noise (S/N) ratio in the entire region from 40to5000cm, at the Canadian Light sources. High resolution combined with a high S/N ratio allowed the recording to be done with an unprecedented resolution of about 0.0017cm.
View Article and Find Full Text PDFJ Phys Chem Lett
January 2025
Molecular Spectroscopy Laboratory, RIKEN, 2-1 Hirosawa, Wako 351-0198, Japan.
Elucidation of the vibrational relaxation process of interfacial water is indispensable for understanding energy dissipation at the aqueous interface. In this study, the vibrational relaxation dynamics of the hydrogen-bonded OH (HB OH) stretch vibration was investigated at the air/isotopically diluted water (HOD-DO) interface by time-resolved heterodyne-detected vibrational sum frequency generation (TR-HD-VSFG) spectroscopy. We observed the temporal change of the excited-state band ( = 1 → 2 transition), which enables a reliable determination of the time of interfacial water.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
January 2025
Department of Chemistry, University of Copenhagen, Universitetsparken 5, Copenhagen Ø, DK-2100, Denmark. Electronic address:
We have recorded the gas phase spectrum of isoprene at room temperature from the mid-infrared range and into the visible range (600 cm to 17050 cm). Absorption spectra were obtained by Fourier transform infrared, conventional dispersion ultraviolet-visible-near-infrared and cavity ring-down spectroscopy to cover the entire range with a resolution comparable to that of the instruments on the James Webb Space Telescope. We have assigned the CH-stretching fundamental and overtone bands corresponding to the Δv=1-6 transitions based on anharmonic vibrational calculations using normal mode and local mode models, for the lower- and higher-energy regions, respectively.
View Article and Find Full Text PDFSpectrochim Acta A Mol Biomol Spectrosc
March 2025
College of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, PR China. Electronic address:
Accurate determination of spectral parameters for carbon monoxide (CO) transitions is crucial for the development of laser absorption spectroscopy-based CO sensors. This study reports the measurement of line strengths, self-broadening coefficients, and their temperature-dependent exponents for three transitions in the first overtone band near 2.3 μm.
View Article and Find Full Text PDFJ Chem Phys
December 2024
Center for Engineering Concepts Development, Department of Mechanical Engineering, University of Maryland at College Park, College Park, Maryland 20742, USA.
In this paper, we develop a model based on a second quantization-with anharmonic phonon scattering and the phonon Boltzmann transport equation-to study precise high-resolution nonequilibrium vibrational energy transfer (VET) under selective phonon excitation in cyclotrimethylene trinitramine. We simulate mid-infrared pump-probe spectroscopy and observe a prompt appearance (<1 ps) of broad-spectrum intensity, which agrees well with experimental data in the literature. The selective excitation of phonons at different frequencies reveals distinct VET pathways and the kinetic evolution of mode occupations as the system reaches a new equilibrium temperature.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!