For neon 3p states excited by transversely polarized electrons, the integrated Stokes parameters, and , have been measured from threshold to 300 eV for the decay photons of 692.9, 667.8 and 717.4 nm wavelengths from the and states, respectively. The and parameters for the 692.9 and 667.8 nm transitions indicate similar excitation mechanisms consistent with their similar ` L S component states'. The non-zero indicates the breakdown of L S -coupling and the large values near threshold suggest a significant exchange process. For the 717.4 nm transition, the three Stokes parameters are much smaller than those of the other two lines. The low is surprising since the large (75.4%) -coupled component state was expected to cause large exchange effects.
The 3s-3p excitation of spin-polarized Na atoms by
Ne+ ions has been studied for impact energies
Elab=200 eV to 6 keV, i.e., in the adiabatic regime. The total excitation cross section and the three Stokes polarization parameters of the fluorescence light have been measured. The linear polarization of the light shows a preferential excitation of the \ensuremath{\Vert}
ml\ensuremath{\Vert}=1 magnetic substates. The circular polarization probes the spin orientation of the excited 3p state. At the highest impact energies investigated the experimental data are compatible with conservation of spin orientation during the collision. With decreasing impact energy, the spin polarization of the final 3p state becomes smaller than the spin polarization of the initial 3s state. This apparent spin depolarization is attributed to the exchange interaction between the Na valence electron and the unfilled
Ne+ 2
p5 core in the quasimolecule formed during the collision.
综合司烧参数 P-i (i = 1， 2,3 ) 为他 3 P-3 -> 2 S-3 (1 )(388.9nm ) 在来自扎根的状态的刺激到以后的转变 3 (3 ) 由一根极化 transverselyspin 的电子横梁的 p 状态在近的阀值精力被测量区域。试验性的结果被介绍。线性极化的 P-2 在事件精力范围上与零一致，提供为联合机制的 LS 的证据 3 (3 ) p 状态。测量圆形的极化 P-3 是非零，显示在极化 thespin 的电子原子碰撞过程的强壮的电子电子交换效果。
Experimental, polarization-dependent excitation spectra for excited-state-Mg--rare-gas-atom optical collisions are reported. In these first studies of the process, polarized Mg atoms in the 3p
1P1 level are produced by absorption of linearly polarized light tuned to the 3s
1S0\ensuremath{\rightarrow}3p
1P1 resonance transition at 285.2 nm. Detuning-dependent, collision-induced polarization spectra are measured in a \ifmmode\pm\else\textpm\fi{}200-${\mathrm{cm}}^{\mathrm{\ensuremath{-}}1}$ range around the Mg 3p
1P1\ensuremath{\rightarrow}5s
1S0 transition at 571.2 nm. The spectra correspond to probing transient Mg-Ne and Mg-Ar molecules on 3p $^{1}\mathrm{\ensuremath{\Pi}}_{1}$\ensuremath{\rightarrow}5s $^{1}\mathrm{\ensuremath{\Sigma}}_{0}^{+}$ and 3p $^{1}\mathrm{\ensuremath{\Sigma}}_{0}^{+}$\ensuremath{\rightarrow}5s $^{1}\mathrm{\ensuremath{\Sigma}}_{0}^{+}$ electronic transitions. Measurements of these excited-state polarization spectra for Mg-Ne optical collisions reveal that for detunings to the red of the atomic Mg 3p
1P1\ensuremath{\rightarrow}5s
1S0 transition, electronic linear polarization greater than 50% survives far into the molecular regime. This represents a direct measure of the polarization important to alignment-dependent inelastic processes in alkaline-earth-metal--rare-gas-atom collisions. The polarization spectra are discussed in terms of existing information on the interatomic potentials and through an axial recoil limit for the polarization degree for parallel and perpendicular molecular transitions. Rate coefficients k for disalignment of Mg 3p
1P1 atoms by collisions with Ar [k=9.4(5)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$
cm3/s] and with Ne [k=6.5(7)\ifmmode\times\else\texttimes\fi{}${10}^{\mathrm{\ensuremath{-}}10}$
cm3/s] are also extracted from the data.
The theory of the cascade level-crossing effect as formulated by Happer is evaluated for zero-nuclear-spin atomic systems and extended to include the case of a polarized initial state. We have used this theory to interpret our cascade-Hanle-effect results (zero-field level crossings) to obtain the lifetime of the two resonance levels,
1s2(1P1) and
1s4(3P1), of the
2p53s configuration of neon. The resonance lines 744 \AA{} ($1{s}_{4}\ensuremath{-}^{1}S_{0}$) and 736 \AA{} ($1{s}_{2}\ensuremath{-}^{1}S_{0}$) are produced in the cascade to the ground
1S0 state when a beam of metastable
1s3(3P0) and
1s5(3P2) neon atoms is excited by selected lines of the $2{p}^{5}3s\ensuremath{-}2{p}^{5}3p$ transition array. Our results are $\ensuremath{\tau}(1{s}_{2})=1.65\ifmmode\pm\else\textpm\fi{}0.16$ nsec and $\ensuremath{\tau}(1{s}_{4})=20.5\ifmmode\pm\else\textpm\fi{}1.5$ nsec.
The Fano-equivalent profiles of two negative-ion resonant states have been observed in the integrated Stokes parameters of 636.2 nm photons emitted from the
3d104s4d1D2 state of zinc. These profiles reflect the effects of electron exchange and the spin-orbit interaction via the angular-momentum-dependent properties of the alignment and orientation Stokes parameters. The resonant states have energies of $10.98\ifmmode\pm\else\textpm\fi{}0.02\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ and $11.33\ifmmode\pm\else\textpm\fi{}0.02\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ and widths of $0.25\ifmmode\pm\else\textpm\fi{}0.03\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$ and $0.33\ifmmode\pm\else\textpm\fi{}0.05\phantom{\rule{0.3em}{0ex}}\mathrm{eV}$, respectively, and are bound to an excited atomic state with a
3d9 core hole. The lower-energy resonance shows a strong spin-orbit interaction whereas the higher-energy resonance shows negligible spin-orbit interaction.