Detection of Atmospheric Species by Laser Spectroscopy

The molecular spectroscopic parameters of atmospheric gases are of great use not only in the atmospheric absorption and chemistry but also in the astrophysics. Based on the high precision of laser spectrometer, now the atmospheric spectroscopy has become one of the most important methods to the trace species analysis and the environmental monitoring. Meanwhile, developments in the laser technology and the self-specialty of non-contact and high sensitivity in spectroscopy make the laser spectroscopy become the main method in these fields of applications. We are focused on the structure and dynamic study of atoms and molecules, and also their applications in the fields of climatology, astronomy, and combustion by developing high precision laser spectroscopy.

High Precision Spectroscopy of Small Molecules

Due to the simplicities of small molecules (hydrogen, water, carbon dioxide molecules, etc), they are natural benchmark systems for testing ground of chemical bonding theories and precise quantum chemistry calculations. With the utilization of laser frequency locking technology, a continuous-wave cavity ring-down spectrometer with kHz precision will be carried out for the high precision spectra measurement of these small molecules. The high quality spectrum will be able to investigate the QED and relativeistic contributions in high accurate quantum chemical calculations, and it will also be possible to measure some fundamental physical constants.

Ultra-high sensitivity CRDS for Trace Species Detection

Cavity ring-down spectroscopy (CRDS), a sensitive and precise diode-laser absorption technique provides long absorption path-length (dozens km) in a compact equipment, is a powerful analytical tool to the in-situ detections of atmospheric trace species (H2O、CO2、NOx and aerosol). And it will be exploited for meteorological and environmental applications.

Reference

  1. Rovibrational line lists for nine isotopologues of the CO molecule in the X1Sigma+ ground electronic state
    G. Li et al., Astrophysical Journal Supplement Series, 216, 15, (2015). [DOI]
  2. Ultra-sensitive, self-calibrated cavity ring-down spectroscopy for quantitative trace-gas analysis
    B. Chen et al., Applied Optics, 53(32), 7716-7723, (2014). [DOI]
  3. Line parameters of the 782 nm band of CO2
    Y. Lu et al., Astrophysical Journal, 775(1), 71, (2013). [DOI]
  4. The 4vCH overtone of 12C2H2, sub-MHz precision spectrum reveals perturbations
    A.-W. Liu et al., Journal of Chemical Physics, 138, 014312, (2013). [DOI]
  5. The v=3<-0 S(0)-S(3) electric quadrupole transitions of H2 near 0.8 um
    S.-M. Hu et al., Astrophysical Journal, 749(1), 76, (2012). [DOI]
  6. Electric-quadrupole transition of H2 determined to 10-9 precision
    C.-F. Cheng et al., Physics Review A, 85(2), 024501, (2012). [DOI]