Energy-pooling collisions between low-lying excited states of Ba have been studied. We have used a CW dye laser to excite the level in Ba. Radiative decay and collisions with Ba or buffer-gas atoms (Ar, He) populate also the , and metastable levels. The spatial density distributions of these excited levels were measured by the absorption of lines from a Ba hollow-cathode lamp as a function of laser frequency. When the laser was on the exact atomic resonance we observed fluorescence from the , , , , , , and states populated by energy-pooling collisions of Ba( , ). By changing the buffer gas pressure the fluorescence intensity ratio between - and - transitions changes dramatically. This is found to be due to redistribution of population among metastable levels, both in magnitude and space. In addition, we have found that the and metastable levels are also populated when the laser is tuned to the blue from the 553.5 nm line under which conditions a pronounced red-shifted light cone (cone emission) is observed.Energy-pooling collisions between low-lying excited states of Ba have been studied. We have used a CW dye laser to excite the level in Ba. Radiative decay and collisions with Ba or buffer-gas atoms (Ar, He) populate also the , and metastable levels. The spatial density distributions of these excited levels were measured by the absorption of lines from a Ba hollow-cathode lamp as a function of laser frequency. When the laser was on the exact atomic resonance we observed fluorescence from the , , , , , , and states populated by energy-pooling collisions of Ba( , ). By changing the buffer gas pressure the fluorescence intensity ratio between - and - transitions changes dramatically. This is found to be due to redistribution of population among metastable levels, both in magnitude and space. In addition, we have found that the and metastable levels are also populated when the laser is tuned to the blue from the 553.5 nm line under which conditions a pronounced red-shifted light cone (cone emission) is observed.

Journal of Physics B Atomic Molecular and Optical PhysicsMay 28, 19968 citations

Collisional Processes Involving the Metastable (6S5D Tripletd(j) Levels of Barium)

E. Ehrlacher

Mar 1, 19930 citations

Energy-pooling collisions in barium

Jonathan Andrew Neuman, Alan C. Gallagher, J. Cooper

Rate coefficients for energy-pooling collisions between low-lying excited states of Ba have been measured. The 6s6p ${(}^{3}$ ${\mathit{P}}_{1}$ ) level in Ba is pumped by a cw diode laser, and radiative decay and collisions with buffer-gas atoms also populate the 5d6s ${(}^{1}$ D) and 5d6s ${(}^{3}$ D) metastable levels. The densities of these low-lying excited states are measured by the absorption of lines from a Ba hollow-cathode lamp, and the states populated by energy-pooling collisions are studied by comparing their fluorescence intensity to that of the laser-excited level. The rate coefficients are on the order of gas-kinetic rates, and they are not strongly dependent on energy defect, spin changes, or angular-momentum changes.Rate coefficients for energy-pooling collisions between low-lying excited states of Ba have been measured. The 6s6p${(}^{3}$${\mathit{P}}_{1}$) level in Ba is pumped by a cw diode laser, and radiative decay and collisions with buffer-gas atoms also populate the 5d6s${(}^{1}$D) and 5d6s${(}^{3}$D) metastable levels. The densities of these low-lying excited states are measured by the absorption of lines from a Ba hollow-cathode lamp, and the states populated by energy-pooling collisions are studied by comparing their fluorescence intensity to that of the laser-excited level. The rate coefficients are on the order of gas-kinetic rates, and they are not strongly dependent on energy defect, spin changes, or angular-momentum changes.

Physical Review AAug 1, 199420 citations

Energy pooling to the

\bf Ba 6s6p ^1P^0_1

level arising from collisions between pairs of metastable

\bf Ba 6s5d ^3D_{J}

atoms

Rate coefficients for energy-pooling collisions between low-lying excited states of Ba have been measured. The 6s6p

{(}^{3}

{\mathit{P}}_{1}

) level in Ba is pumped by a cw diode laser, and radiative decay and collisions with buffer-gas atoms also populate the 5d6s

{(}^{1}

D) and 5d6s

{(}^{3}

D) metastable levels. The densities of these low-lying excited states are measured by the absorption of lines from a Ba hollow-cathode lamp, and the states populated by energy-pooling collisions are studied by comparing their fluorescence intensity to that of the laser-excited level. The rate coefficients are on the order of gas-kinetic rates, and they are not strongly dependent on energy defect, spin changes, or angular-momentum changes.