Mei-Ju Lu

Cold TiO(X3Δ)–He collisions

We use laser ablation and cryogenic helium buffer-gas cooling to produce large numbers of X3?1?TiO molecules at a translational temperature of 5?K. We investigate their cold collisions with helium and measure elastic and inelastic scattering cross-sections. As expected for 3? molecules, which have large spin?rotation couplings, TiOs inelastic m-changing collision cross-section is large: on the same order as its momentum transfer cross-section.

Valence-shell single photoionization of Kr+ ions: Experiment and theory

Photoionization of Kr

Inelastic collisions of CaH with He at cryogenic temperatures

^+

Electromagetically induced transparency with nuclear spin.

ions was studied in the energy range from 23.3 eV to 39.0 eV at a photon energy resolution of 7.5 meV. Absolute measurements were performed by merging beams of Kr

Valence-shell single photoionization of chlorine-like K 2 + ions: Experiment and theory

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Fine-structure resolved photoionization of metastable Be-like ions C III, N IV, and O V

ions and of monochromatized synchrotron undulator radiation. Photoionization (PI) of this Br-like ion is characterized by multiple Rydberg series of autoionizing resonances superimposed on a direct photoionization continuum. Resonance features observed in the experimental spectra are spectroscopically assigned and their energies and quantum defects tabulated. The high-resolution cross-section measurements are benchmarked against state-of-the-art theoretical cross-section calculations from the Dirac-Coulomb R-matrix method.

Photoionization and electron-impact ionization of Kr{sup 3+}

Using helium buffer gas cooling, we have prepared dense samples of ground-state molecular calcium monohydride (CaH X 2Σ) at cryogenic temperatures. We have used optical pumping to polarise the spin state of the CaH molecules and we have measured the inelastic collisions of molecular CaH with atomic helium at temperatures from 2 to 7 K. The measured CaH electronic spin depolarisation rate coefficient increases rapidly with increasing temperature, increasing from 2 × 10−13 cm3 s−1 to over 10−11 cm3 s−1. The strong dependence of rate coefficient on temperature is attributed to the CaH population in the first excited rotational state.

Chemical Reactions of Atomic Lithium and Molecular Calcium Monohydride at 1 K

We report the observation of electromagnetically induced transparency in a sample of cryogenically cooled ground-state atomic ytterbium ((1)S(0)). The transparency is produced due to coherence between the optical field and the nuclear spin state of the (173)Yb nucleus. Because the nuclear spin states interact very weakly with their environment, they are resistant to decoherence due to inelastic collisions and inhomogenous fields. Consequently, atomic ensembles of pure nuclear spin states may be a superior medium for a variety of nonlinear optics and quantum information experiments.

Fine-structure-changing collisions in atomic titanium

The absolute single photoionization cross-section was measured for Cl-like K

Valence-shell photoionization of the chlorinelike Ca3+ ion

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