Noble-gas broadening rates for barium transitions involving the metastable 6s5d 3DJ levels.

摘要: The collisional-broadening rate coefficients, for both helium and argon buffer gases, have been measured transitions from the metastable 6s5d $^{3}$${\mathit{D}}_{\mathit{J}}$ levels in barium. A weak cw diode laser was used to populate manifold through optical pumping of 6${\mathit{s}}^{2}$ $^{1}$${\mathit{S}}_{0}$\ensuremath{\rightarrow}6s6p $^{3}$${\mathit{P}}_{1}$ transition, followed by radiative decay into $^{3}$${\mathit{D}}_{2,1}$ states. absorption coefficient transition interest then monitoring transmission a very probe beam as its frequency scanned over line shape. Such scans were carried out several (pump) powers, using standard line-shape normalization integral, we able construct density-independent shapes. Each spectral shape consists many hyperfine components due presence five barium isotopes (including two with nonzero nuclear spin). component is affected Doppler, pressure, natural broadening and, therefore, can be represented Voigt function. Thus, shapes (recorded 50, 100, 200, 500 Torr either He or Ar gas) fitted sum functions which only free parameter pressure-broadening rate. Using least-squares fit rates versus buffer-gas number density, broadening-rate coefficients ${\mathit{k}}_{\mathrm{br}}$ found. In addition, collisional shifts these measured, shift ${\mathit{k}}_{\mathrm{shift}}$ determined.