We have measured the broadening of ${\mathrm{Rb}}^{87}$ level-crossing signals due to collisions with ${\mathrm{Rb}}^{85}$ . The depolarization or broadening rates for the $5^{2}P_{\frac{1}{2}}$ state orientation, the $5^{2}P_{\frac{3}{2}}$ state orientation and alignment, and the $5^{2}P_{\frac{3}{2}}$ state 58-G crossing were measured. Theoretical resonance-broadening depolarization rates for the electronic angular momentum, due to Carrington, Stacey, and Cooper, have been incorporated into calculations of the Hanle-effect signals in the presence of nuclear-spin coupling. The experimental broadening rates are corrected for a minor amount of coherence narrowing. The measured broadening rate for the three $5^{2}P_{\frac{3}{2}}$ state level-crossing signals are in 20% agreement with the theory. The measured $5^{2}P_{\frac{1}{2}}$ state broadening rate exceeds the theoretical by about a factor of 2. This discrepancy may be due to the action of the hyperfine interaction during these unusually long duration collisions. The natural lifetimes of the $5^{2}P_{\frac{3}{2}}$ and $5^{2}P_{\frac{1}{2}}$ states are determined from the low-density linewidth to be 27.0 \ifmmode\pm\else\textpm\fi{} 0.5 and 29.4 \ifmmode\pm\else\textpm\fi{} 0.7 nsec, respectively.We have measured the broadening of ${\mathrm{Rb}}^{87}$ level-crossing signals due to collisions with ${\mathrm{Rb}}^{85}$. The depolarization or broadening rates for the $5^{2}P_{\frac{1}{2}}$ state orientation, the $5^{2}P_{\frac{3}{2}}$ state orientation and alignment, and the $5^{2}P_{\frac{3}{2}}$ state 58-G crossing were measured. Theoretical resonance-broadening depolarization rates for the electronic angular momentum, due to Carrington, Stacey, and Cooper, have been incorporated into calculations of the Hanle-effect signals in the presence of nuclear-spin coupling. The experimental broadening rates are corrected for a minor amount of coherence narrowing. The measured broadening rate for the three $5^{2}P_{\frac{3}{2}}$ state level-crossing signals are in 20% agreement with the theory. The measured $5^{2}P_{\frac{1}{2}}$ state broadening rate exceeds the theoretical by about a factor of 2. This discrepancy may be due to the action of the hyperfine interaction during these unusually long duration collisions. The natural lifetimes of the $5^{2}P_{\frac{3}{2}}$ and $5^{2}P_{\frac{1}{2}}$ states are determined from the low-density linewidth to be 27.0 \ifmmode\pm\else\textpm\fi{} 0.5 and 29.4 \ifmmode\pm\else\textpm\fi{} 0.7 nsec, respectively.

Physical Review AJul 1, 197437 citations

Non-stationary Raman scattering of light in gas atoms without nuclear spin in the presence of elastic depolarising collisions

A. I. Alekseev, V N Beloborodov, O. V. Zhemerdeev

A theoretical investigation of the non-stationary Raman scattering (RS) of light in gas atoms with no nuclear spin has been made. Account was taken of the level degeneracy due to the different orientation of the total angular momenta, the dependence of the RS signal on the polarisations of the light pulses and of the elastic depolarising collisions. Interesting RS polarisation properties have been found and assumed as a basis method for the identification of optically forbidden transitions and for the determination of parameters of the cubic susceptibility tensor. It has been proved that the polarisation properties and damping law of the non-stationary RS signal permit multipole relaxation rates of forbidden and allowed atomic transitions to be determined.A theoretical investigation of the non-stationary Raman scattering (RS) of light in gas atoms with no nuclear spin has been made. Account was taken of the level degeneracy due to the different orientation of the total angular momenta, the dependence of the RS signal on the polarisations of the light pulses and of the elastic depolarising collisions. Interesting RS polarisation properties have been found and assumed as a basis method for the identification of optically forbidden transitions and for the determination of parameters of the cubic susceptibility tensor. It has been proved that the polarisation properties and damping law of the non-stationary RS signal permit multipole relaxation rates of forbidden and allowed atomic transitions to be determined.

Journal of Physics B Atomic and Molecular PhysicsJul 28, 19875 citations

The Determination of Atomic Wave Functions

Louis C. Green

Jan 1, 19550 citations

Studies on the excitation mechanism and ionization probability of atomic multi-channel photo-excitation and ionization processes

Xiaoyong Lu, Lide Wang, Junyao Zhang

Atomic selective ionization processes provide critical ionization probability and isotopic selectivity in laser isotope separation. Aimed at the general principles of transition cross sections and ionization probabilities under various atomic hyperfine structures and laser parameters, and the optimization of atomic multi-channel photo-excitation and ionization processes of non-zero nuclear spin isotopes, the semi-classical density matrix theory of an imaginary two-step photoionization process is established with the consideration of magnetic sublevels of near-resonantly excited hyperfine levels. For determining the dimensionless transition cross sections of hyperfine transition channels, two methods are proposed in this article, i.e. the saturated excitation line-shape comparison method and weak excitation signal strength method, and a good agreement is achieved between numerical dimensionless transition cross sections and experimental results for several non-zero nuclear spin isotopes. The dependence of saturated ionization probability on laser polarization is studied systematically, and the hyperfine transition of Δ F = +1 is found to be superior to Δ F = −1, 0 in terms of saturated ionization probability. A general formula of oversaturated ionization probability is summarized for different hyperfine transitions. An interesting phenomenon called “magnetic sublevel coherence trapping” is employed to explain the inadequate ionization probability of the Δ F = −1 hyperfine transition even under the oversaturated excitation condition, and its mechanism is discussed through the temporal evolution of the density matrix elements. These numerical studies can provide beneficial references for laser isotope separation of isotopes with non-zero nuclear spin, as well as atomic laser spectroscopy.Atomic selective ionization processes provide critical ionization probability and isotopic selectivity in laser isotope separation. Aimed at the general principles of transition cross sections and ionization probabilities under various atomic hyperfine structures and laser parameters, and the optimization of atomic multi-channel photo-excitation and ionization processes of non-zero nuclear spin isotopes, the semi-classical density matrix theory of an imaginary two-step photoionization process is established with the consideration of magnetic sublevels of near-resonantly excited hyperfine levels. For determining the dimensionless transition cross sections of hyperfine transition channels, two methods are proposed in this article, i.e. the saturated excitation line-shape comparison method and weak excitation signal strength method, and a good agreement is achieved between numerical dimensionless transition cross sections and experimental results for several non-zero nuclear spin isotopes. The dependence of saturated ionization probability on laser polarization is studied systematically, and the hyperfine transition of Δ F = +1 is found to be superior to Δ F = −1, 0 in terms of saturated ionization probability. A general formula of oversaturated ionization probability is summarized for different hyperfine transitions. An interesting phenomenon called “magnetic sublevel coherence trapping” is employed to explain the inadequate ionization probability of the Δ F = −1 hyperfine transition even under the oversaturated excitation condition, and its mechanism is discussed through the temporal evolution of the density matrix elements. These numerical studies can provide beneficial references for laser isotope separation of isotopes with non-zero nuclear spin, as well as atomic laser spectroscopy.

Journal of Quantitative Spectroscopy and Radiative TransferApr 22, 20251 citation

Atomic Coherences and Level-Crossings Physics

V. Bommier

Springer eBooksJan 1, 19963 citations

We have measured the broadening of

{\mathrm{Rb}}^{87}

level-crossing signals due to collisions with

{\mathrm{Rb}}^{85}

. The depolarization or broadening rates for the

5^{2}P_{\frac{1}{2}}

state orientation, the

5^{2}P_{\frac{3}{2}}

state orientation and alignment, and the

5^{2}P_{\frac{3}{2}}

state 58-G crossing were measured. Theoretical resonance-broadening depolarization rates for the electronic angular momentum, due to Carrington, Stacey, and Cooper, have been incorporated into calculations of the Hanle-effect signals in the presence of nuclear-spin coupling. The experimental broadening rates are corrected for a minor amount of coherence narrowing. The measured broadening rate for the three

5^{2}P_{\frac{3}{2}}

state level-crossing signals are in 20% agreement with the theory. The measured

5^{2}P_{\frac{1}{2}}

state broadening rate exceeds the theoretical by about a factor of 2. This discrepancy may be due to the action of the hyperfine interaction during these unusually long duration collisions. The natural lifetimes of the

5^{2}P_{\frac{3}{2}}

and

5^{2}P_{\frac{1}{2}}

states are determined from the low-density linewidth to be 27.0 \ifmmode\pm\else\textpm\fi{} 0.5 and 29.4 \ifmmode\pm\else\textpm\fi{} 0.7 nsec, respectively.