Rydberg series in the visible two-photon optogalvanic spectrum of neon

Petr Kubelík, Adam Pastorek, Svatopluk Civiš

Naveed K. Piracha, B Suleman, S H Khan +1 more

We report extensive new data on the single-colour two-photon optogalvanic spectra of neon in the visible region. The experimental method enables us to record a pure two-photon spectrum in a region which is full of one-photon transitions. A large number of two-photon transitions originating from two metastable 3s(3/2) 2 , 3s'( 1/2 ) 0 states and one non-metastable 3s(3/2) I state of the 2p 5 3s configuration of neon have been recorded and arranged into 19 Rydberg series. The interchannel interactions among the overlapping Rydberg series have been studied using the multichannel quantum defect theory.

Gerard T. Higgins

Matthias Moos, Razmik G. Unanyan, Michael Fleischhauer

M. A. Zia, Muhammad Aslam Baig

We present new experimental data on the highly excited levels in mercury using the optogalvanic detection technique in conjunction with a dc discharge cell. The collisionally populated 6s6p 3P2 metastable level has been used as an intermediate level to access the Rydberg states using a frequency-doubled dye laser covering the wavelength region between 370 and 249 nm. The optogalvanic data reveal 6sns 3S1(13≤n≤50), 6snd 2D1(6≤n≤18), 6snp 3D1(6≤n≤14), 6snd 3D2(6≤n≤15), and 6snd 3D3(6≤n≤59) Rydberg series. The 6sns 3S1 and 6snd 3D3 Rydberg series to such a high n value have been reported for the first time. In addition, collisionally induced parity-forbidden transitions 6snp 3P1(44≤n≤50) have been detected.

Niels J. Kylstra, Martin Dörr, C. J. Joachain +1 more

We present non-perturbative ab initio calculations of resonant two-photon ionization in which the ground state of a complex atom is resonantly coupled by a laser field to two Rydberg states, each of which belongs to a different Rydberg series. As an example, we have studied the resonant two-photon ionization of neon via the 5s and 4d Rydberg states using the R-matrix-Floquet theory. We find that for weak fields, where the Rydberg states are not overlapping, interference effects are already present which lead to a suppression of ionization for a particular laser frequency. For strong fields, the field induced coupling between the two Rydberg states can strongly modify the weak-field behaviour. We give a qualitative explanation of these phenomena by considering the dressed states of a simple three-level model atom coupled to two continua. Finally we show, by varying the intensity, how the Floquet eigenstates corresponding to the ground state and the two Rydberg states of neon are adiabatically connected to the field-free states. © 1995 IOP Publishing Ltd.