Microwave spectroscopy of Al I Rydberg states: F terms

J. Phys. B: At. Mol. Opt. Phys.

Ефремов

Gerasimov

et al. 2003

Self Cite

We present results of microwave and millimetre-wave resonance measurements in D, F and G Rydberg states of neutral aluminium in the frequency range 4-423 GHz for principal quantum numbers n = 22-43. In all, 12, 27 and 19 resonances of nF2 D 5/2 and nF → nG or nF → (n + 1)G series, respectively, have been recorded. D-state fine-structure doublet splittings have been obtained with accuracy ±1.4 MHz. For D and G states, quantum defect Ritz-expansion parameters have been determined, from which the Rydberg series can be accurately reconstructed to an accuracy of order ±1 MHz (3 × 10 −5 cm −1 ) for all n.

“…Two-photon resonances connecting nF and (n + 1)F levels were reported in paper I [15]. The D levels are indexed according to Moore [5].…”

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Microwave spectroscopy of Al I atoms in Rydberg states: D and G terms

J. Phys. B: At. Mol. Opt. Phys.

Ефремов

Gerasimov

et al. 2003

Self Cite

“…Earlier we have fulfilled extensive study of microwave absorption spectra of Al atom in Rydberg S, P, D, F states [7][8][9]. As a results we have obtained the sets of constants for calculation of quantum defect in S, P, D, and F states that fit best of all both microwave absorption spectra and optical spectra published by the authors of the works [1][2][3][4][5].…”

mentioning

confidence: 95%

Specification of the Ionization Potential of AlI

Ефремов

2006 International Workshop on Laser and Fiber-Optical Networks Modeling

Gerasimov

et al. 2006

A joint analysis of high-precision microwave measurements of transition frequencies of Al atoms in S, P, D, and F Rydberg states obtained by the authors and spectroscopic data from optic wavelength range allowed us to determine a new value for ionization potential of Al atoms V IP = 48278,53±0,02 cm -1 .Ionization potentials V IP of atoms and molecules are fundamental quantities of great importance in many areas of physics and chemistry. They provide crucial information on the electronic structure and, therefore, are often used as benchmarks for theoretical methods. Also when used in the appropriate thermodynamic cycles, V IP relate to bond strengths. The accuracy of calculation of ionization potentials of multi electron atoms for the time being is not satisfactory and that is why they are determined using experimental methods: method of surface ionization, method of electron impact, method of spectral extrapolation, method of two and three stage ionization, and method of fitting Rydberg series. The last method is accepted as providing the highest accuracy of 1 cm -1 and higher. The authors of works [1][2][3][4][5] used this method to determine the ionization potential of Al atoms. We propose a method of specification of the ionization potential that based on the joining of the most accurate direct measurements of transition frequencies from the ground state to the excited states of the atom in optic wavelength range T nlj with highprecision calculations of atomic energy E(n,l,j) in Rydberg states. We used this method earlier for specification of ionization potential of Au I [6]. In the present paper we apply this method to the specification of ionization potential V IP of aluminum. Therefore we have:

“…

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mentioning

confidence: 99%

“…+380577203734, fax. +380577203758, e-mail: ealekseev@rian.kharkov.ua 2Institute of Physics of Semiconductors, Siberia division of Russian Academy of Sciences, 13, Lavrentyev Av., 630090, Novosibirsk, Russia Spectroscopy of atoms in Rydberg states was an object of extensive investigation (see for example [1][2][3][4][5] and references therein). Usually necessary population of Rydberg states is achieved by means of multi-stage pulse laser pumping.…”

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confidence: 99%

Time-dependent registration of ionization current for spectroscopy of rydberg atoms

2010 International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter and Submillimeter Waves

Alekseev

Захаренко

et al. 2010

Spectroscopy of atoms in Rydberg states was an object of extensive investigation (see for example [1][2][3][4][5] and references therein). Usually necessary population of Rydberg states is achieved by means of multi-stage pulse laser pumping. That is why useful signal of ionization current from Single Channel Electron Multiplier (CEM or channeltron) is also pulse signal. Essential temporal instability of this signal is one of the main problems during its registration. More over in order to investigate Rydberg spectra of elements with high value of ionization potential (AI, Cu, Au etc.) it is necessary to apply high-temperature source of atoms (up to 2000 -3000K). That is why there appears effect of redistribution of population by means of black body radiation. This effect makes additional difficulties to study ionization spectra.In order to overcome these obstacles we propose to apply time-dependent registration of ionization current from CEM. First of all such approach will allow us to store individual time-dependent realizations and to provide averaging of these realizations numerically excluding temporal instability. In addition after improvement of the receiving system it will be possible to detect ionization spectra resolving Rydberg states populated by means of black body radiation.The proposed time-dependent registration of ionization current is provided by a system which includes ADC and buffer RAM. Its structure is shown in the fig. 1. In order to detect very fast processes as well as rather slow ones it contains two independent channels. The fast channel includes input amplifier, fast ADC, fast FIFO, and controlling logic (see fig.l). At a moment this channel has 25 ns time resolution and FIFO capacity 2048Bytes. It allows us to capture a realization with duration about 50/ls. The fast channel operates as follows. A laser pulse sets RS-trigger which opens a gate and enables start of ADC every 25ns storing its measurements in FIFO. When FIFO is full it generates "STOP" signal which resets RS-trigger, closes the gate, and stops measurements. At the same time this signal generates external interrupt of ADuC841 in order to initiate data reading from FIFO.The slow channel is based on the internal ADC of ADuC841 with DMA mode. In order to increase maximal duration of investigated signal we apply external RAM of 32 kBytes. This slow channel also contains input buffer in order to match impedances and some additional logic which is necessary to apply external RAM.The time resolution of this channel is 2.5/ls. It allows us to capture a realization with duration up to 80 ms.Application of ADuC84I provides also communication with computer. All captured realizations are transferred to computer using RS-232 interface for further processing and averaging.As it is known investigated Rydberg states are pumped by means of one or several pulse lasers which require thorough manual adjustment. Usually laser pulse-repetition frequency is about 1 -20 Hz. So there are some difficulties to observe useful signal during adjustmen...