First experimental evidence of an antiresonance in the two-photon ionization of Cs atoms

Sihong Gu, Shunsheng Gong, Bingmo Liu +3 more

S. I. Lavrinenko, Vitalii G Pal'chikov

Ernst H.A. Granneman, Marnix J. van der Wiel

Measurements are reported of two-photon ionization probabilities in atomic Cs at the nine wavelengths of the Ar ion laser (5145-4545 AA), the first step of the two-photon process occurring to intermediate levels in the vicinity of the 7 2 P 1/2,3/2 levels. Additional ionization due to molecular Cs was monitored by ion time-of-flight analysis and found to be negligible when choosing proper oven temperatures. An absolute scale for the two-photon rates is provided by normalization on a one-photon UV cross section. Comparison of our data with calculations based on quantum defect Coulomb wavefunctions shows discrepancies of up to four orders of magnitude.

Didier Normand, G. Petite, J. Morellec

Zhifeng Cui

The rate-equation and the Laplace transformation were used to study the three photons resonant ionization process of three-level system,and the analytical formulas of the resonant state populations and the ionization probabilities were obtained.By using this formulas to study the(1+1′+1′)resonant ionization process of Cs atom which are excited to the 6p(P_(3/2))、7d(D_(3/2)) resonant state from the ground state 6s(S_(1/2)) by the first two photons following the ionization by the third photon,the influence of the laser intensity and pulse width on the resonant state populations and ionization efficiency were investigated.The conditions of the laser intensity to evacuate the two resonant states population were also presented respectively.

Chun Li

In order to explain some characteristics discovered in the experimental study of the collisional ionization of Rydberg Cs atoms with CCl 4 molecules, two corrections were made to the quasi free electron mode, commonly used to describe the collsional ionization of Rydberg atoms with molecules:(1)the influence of the core and the quantum defect of Rydberg atom were taken into account;(2)the separation probability of the product ion pair was calculated. With this corrected model, a theoretical result in good agreement with our experiment measurements was obtained. A comparison with another reported experimental result was also made.