Radiative lifetimes of highly excited states in rubidium
2014 Measurements have been made of the natural radiative lifetimes of highly excited rubidium (9 ~ n ~ 18) S and D states. These results, as well as those already published concerning P and F states, agree well with the theoretical lifetimes calculated by the Bates-Damgaard method. J. Physique 41 (1980) 119-121 1 FTVRIER 1980, Classification Physics Abstracts 32.70 In the past few years, measurements of the radiative lifetimes of highly excited states of alkali atoms have been reported [1-3]. These results would clearly be of interest for physicists working in atomic physics, plasma physics, astrophysics. Moreover they allow interesting comparisons with theoretical calculations. We have already published measurements of the radiative lifetimes for some Rydberg P and F states in rubidium [4, 5]. In order to obtain a consistent set of lifetime values for a given alkali atom, we present here measurements concerning the nS and nD states of rubidium (9 n 18). Comparison is given between the obtained experimental values and the theoretical ones calculated by using a modified Bates-Damgaard Method [6, 7] (here after refered as B.D.). We use the classical method of time resolved laser induced fluorescence [4]. Rubidium atoms contained in a cell are excited in a given high-lying nS or nD state by stepwise pulsed excitation via the first resonant 5P state. For convenience the 5p3,2 state is chosen as the intermediate state for the excitation of the nS levels, the observation of the population decay being made on the nS -+ 5P 1/2 line. The nD states are produced by using light pulses whose wavelengths correspond either, to the 5PI/2 --+ nD3/2 transitions for n 13, or to the 5P3/2 -+ nD3/2,5/2 transitions for n &#x3E; 13; the population decay is observed on these same lines. Such a choice is determined by the fact that we are also interested in the study of some collisional properties of the nD states (results concerning the collisional properties of both the S and D levels will be published elsewhere [8]). Thus our reported lifetimes refer to the nD3/2 states for n 13 and to the nD states, without allowance for fine structure, for n &#x3E; 13. This is of no importance since the lifetimes corresponding to the two fine structure levels are expected to be very close, for a given n value. A high-speed photon counting system allows the determination of the decay of the excited.state population as a function of time for a given rubidium pressure. The extrapolation to zero rubidium pressure yields the natural radiative lifetime. The experimental set-up, shown in figure 1, has been already widely Fig. 1. Experimental set-up. Article published online by EDP Sciences and available at http://dx.doi.org/10.1051/jphys:01980004102011900
Bibliography on Atomic Transition Probabilities (November 1977 through March 1980). Supplement 1.
Abstract : This is the first supplement to the NBS Special Publication 505, Bibliography on Atomic Transition Probabilities (1914 through October 1977), and it covers the literature on the subject from November 1977 through March 1980. It contains approximately 600 references, with each article assigned a number, and is divided into five main sections. The first section contains a fisting, by number, of articles of general interest. The second section lists by number all articles containing numerical data; it is arranged by element and stage of ionization and is further subdivided according to theoretical and experimental methods, comments, and compilations. The third section contains a listing of all articles, including numbers, authors, title, and journal reference; it is arranged by year of publication and alphabetically by authors names within the year. All foreign language papers are identified, and their titles are translated into English. The fourth section contains a listing of all authors and the numbers of the papers they have authored or co-authored. A final section provides corrections or additions to the preceding bibliography. (Author)
Calculation of the Gamma Function by Stirling's Formula
In this paper, we derive a simple error estimate for the Stirling formula and also give numerical coefficients. Stirling's formula is: log r(s) - (s - 2) log s - s + 2 log 27r