Direct measurements of collisionally broadened Raman linewidths of CO2 S-branch transitions Academic Article uri icon

abstract

  • We report direct measurements of S-branch Raman-coherence lifetimes of CO(2) resulting from CO(2)-CO(2) and CO(2)-N(2) collisions by employing time-resolved picosecond coherent anti-Stokes Raman scattering spectroscopy. The S-branch (ΔJ = +2) transitions of CO(2) with rotational quantum number J = 0-52 were simultaneously excited using a broadband (~5 nm) laser pulse with a full-width-at-half-maximum duration of ~115 ps. The coherence lifetimes of CO(2) for a pressure range of 0.05-1 atm were measured directly by probing the rotational coherence with a nearly transform-limited, 90-ps-long laser pulse. These directly measured Raman-coherence lifetimes, when converted to collisional linewidth broadening coefficients, differ from the previously reported broadening coefficients extracted from frequency-domain rotational Raman and infrared-absorption spectra and from theoretical calculations by 7%-25%.

author list (cited authors)

  • Roy, S., Hsu, P. S., Jiang, N., Gord, J. R., Kulatilaka, W. D., Stauffer, H. U., & Gord, J. R.

publication date

  • January 1, 2013 11:11 AM