Multiphoton excitation and ionization of atoms and molecules (original) (raw)

Multiphoton Ionization of Molecular Cesium with a Tunable Dye Laser

Physical Review A

This payer reports the observation of the two-photon ionization of molecular cesium as a continuous function of laser wavelength in the 6200-6600-A region with a tunable dye laser having a 0.18-cm ' linewidth. To the author's knowledge, it serves to illustrate the first extension to neutral molecular species of the important techniques of resonant multiphoton photodetachment spectroscopy. The resulting two-photon photoionization spectrum is intepreted in terms of the vibrational structure of the resonant intermediate molecular state.

The resonant 4d photoemission spectrum of atomic cesium

Journal of Electron Spectroscopy and Related Phenomena, 2005

In this work we have studied the 4d photoexcitation of atomic cesium vapor at high resolution in the energy range 75-90 eV. Below threshold, the two series of the 4d 10 6s → 4d 9 6s6p 3,1 P discrete transitions are observed to dominate the measured ion-yield spectra. The high photon energy resolution allowed us to selectively excite specific resonances. In this way the decay of the different excited states lying close to each other could be followed with a minimum of interference from overlapping transitions. Here we present the resonant Auger spectra recorded at the lowest energy 4d excited states and a preliminary analysis based on previous experimental and theoretical results.

Photoionization of laser-excited caesium atoms above the 4d ionization threshold

Journal of Physics B: Atomic, Molecular and Optical Physics, 2010

The photoionization of ground state and 6p laser-excited Cesium atoms was studied above their 4d ionization threshold. The 4d photoelectron spectrum of 6p laser-excited atoms shows a stronger excitation of satellites upon ionization than its ground state counterpart. The relative intensities of satellite and main photolines show a slow variation with the incoming photon energy for both the ground state and the 6p laser-excited states. An assignment of the excited state spectra, supported by recently published ground state photoionization spectra and calculations, is given and a preliminary analysis of the 4d Auger spectrum of laser-excited atoms is also presented.

Strong-field two-photon absorption in atomic cesium: an analytical control approach

Optics Express, 2009

We have considered an analytical control of two-photon absorption process of atoms in the strong-field interaction regime. The experiment was performed on gaseous cesium atoms strongly interacting with a shaped laser-pulse from a femtosecond laser amplifier and a programmable pulse-shaper. When this shaped laser-pulse transfers the atomic population from the 6s ground state to the 8s excited state, we have found that both positively-and negatively-chirped laser pulses, compared with a Gaussian pulse, enhance this excitation in the strong-field regime of laser-atom interaction. This unusual phenomena is explained because the temporal shape of the laser intensity compensates the effect of dynamic Stark shift for the two-photon resonant condition to be optimally maintained. We provide analytic calculations using the strong-field phase matching, which show good agreement with the experiment.

Laser resonance ionization spectroscopy of the cerium atom

Journal of Physics B: Atomic, Molecular and Optical Physics, 1997

About 70 odd-parity high-lying levels have been observed as a result of two-step laser excitation and electric field ionization. The energies are determined from the registered dependence of the observed ion signal on the wavelength of the exciting laser radiation by adding the known first step frequency. The maximum experimental error is ∼1 cm −1 . The investigation also includes the estimation of the radiative lifetime of some Rydberg states. The ion signal as a function of the ionizing electric field delay is considered to represent the radiative decay curve and is used for estimating the radiative lifetime. New results on the highly excited levels have been obtained.

Electron-impact ionization cross sections out of the ground and 6^{2}P excited states of cesium

Physical Review A, 2006

An atom trapping technique for determining absolute, total ionization cross sections ͑TICS͒ out of an excited atom is presented. The unique feature of our method is in utilizing Doppler cooling of neutral atoms to determine ionization cross sections. This fluorescence-monitoring experiment, which is a variant of the "trap loss" technique, has enabled us to obtain the experimental electron impact ionization cross sections out of the Cs 6 2 P 3/2 state between 7 eV and 400 eV. CCC, RMPS, and Born theoretical results are also presented for both the ground and excited states of cesium and rubidium. In the low energy region ͑Ͻ11 eV͒ where best agreement between these excited state measurements and theory might be expected, a discrepancy of approximately a factor of five is observed. Above this energy there are significant contributions to the TICS from both autoionization and multiple ionization.

Photoassociation of cesium atoms into the double minimum state

Chemical Physics Letters, 1999

We have observed the transition from the free colliding pair of cesium atoms into the outer well of the double minimum Cs 3 1 S q state. This photoassociation process takes place in a cesium vapor consisting predominantly of atoms, in which 2 u dimers have been about 85% thermally dissociated. Excellent agreement with quasiclassical simulations was found. We discuss the possibility of using a double minimum Cs 3 1 S q state for the formation of ultracold Cs X 1 S q molecules.