Laboratory atomic spectroscopy experiments

The ab initio calculations of atomic structures are often dictated by high resolution spectroscopy laboratory experiments or by astrophysical observations that require reliable atomic parameters for their interpretation. The spectacular increase of the spectral resolution during the last two decades, in aU domains of the electromagnetic spectrum, forced the theoreticians to improve their models and computational tools to achieve the needed accuracy in their atomic structures and dynamical properties calculations. This applies not only to laboratory measurements but also to observational spectroscopy for astrophysics and astronomy thanks to high resolution spectrometers coupled to ground-based or space telescopes. 

In Chap. 1 is written by Saburo Nasu, the reader will find a general introduction to Mossbauer Spectroscopy. What is the Mossbauer effect and What is the characteristic feature of Mossbauer spectroscopy These questions are answered briefly in this chapter. Mossbauer spectroscopy is based on recoilless emission and resonant absorption of gamma radiation by atomic nuclei. Since the electric and magnetic hyperfine interactions of Mossbauer probe atom in solids can be described from the Mossbauer spectra, the essence of experiments, the hyperfine interactions and the spectral line shape are discussed. A few typical examples are also given for laboratory experiments and new nuclear resonance techniques with synchrotron radiation. 

This calculation also shows that spontaneous magnetic dipole emission in the radio or microwave region will be quite unobservable in laboratory experiments. The techniques of radio frequency spectroscopy of atoms and nuclei in solids, liquids, and gases therefore depend on the stimulated emission and absorption processes wliich are discussed in detail in Chapter 9. 

Recently in our laboratory we have initiated a program to study the photoabsorption processes of metal vapors throughout the UV and EUV region. Our research interests are (1) to obtain the absolute cross section measurement of atomic and molecular metal vapors, (2) to study the photoionization processes of molecular metal species, and (3) to study the photodissociation processes of molecular metal ions. Several experimental methods such as the heat-pipe absorption spectroscopy, photoionization mass spectroscopy, and electron-ion coincidence technique, will be used in the study. This report summarizes our first experiment using heat-pipe absorption spectroscopy. 

A few comments concerning the crystallization of carbanions are in order. These comments are based upon the personal experience developed in our own laboratory and also upon observations noted in the literature in the course of crystallizing enolate anions. Although alkali metal enolate anions are relatively unstable compounds, they have been prepared in the solid state, isolated, and characterized by IR and UV spectroscopy in the 1970s. Thus the ot-lithiated esters of a number of simple esters of isobutyric acid are prepared by metallation of the esters with lithium diisopropylamide in benzene or toluene solution. The soluble lithiated esters are quite stable at room temperature in aliphatic or aromatic hydrocarbon solvents and are crystallized out of solution at low temperature (e.g. -70 °C.). Alternatively the less soluble enolates tend to precipitate out of solution and are isolated by centrifugation and subsequent removal of the solvent. Recrystallization from a suitable solvent can then be attempted. The thermal stability of the lithiated ester enolates is dramatically decreased in the presence of a solvent with a donor atom such as tetrahydrofuran. 

Interactive Analytical Chemistry CD-ROM. Developed by William J. Vin-ing. University of Massachusetts, Amherst, in conjunction with the text authors, this CD-ROM is packaged free with every copy of the book. Prompted by icons with captions in the text, students explore the corresponding Intelligent Tutors, Guided Simulations, and Media-based Exercises. This CD-ROM includes tutorials on statistics, equilibria, spectrophotometry, electroanalytical chemistry, chromatography, atomic absorption spectroscopy, and gravimetric and combustion analysis. Also included on the CD-ROM as an Adobe Acrobat PDF file is Chapter 37, Selected Methods of Analysis. Students will be able to print only those experiments that they will perform, and the printed sheets can be easily used in the laboratory. 

An example where nonlinear phenomena in connection with laser-rf spectroscopy have been used in atomic beams, is the recent work on calcium isotopes carried out in our laboratory. The goal of these experiments was to determine nuclear electric quadrupole moments from precise hyperfine structure data of the atomic spectrum. This is of some importance in the case of calcium, since Ca as well as Ca are so-called double-magic nuclei, i.e., with closed proton and neutron shells. Radioactive Ca (t = 1.03 X 10 yr) and the stable isotope Ca have been investigated by laser-rf spectroscopy. The measurements allow to study the influence of a single neutron and three neutrons, respectively, on the double-magic °Ca core. 

This book is intended as an introduction to the basic methods and instrumentation of spectroscopy, with special emphasis placed on laser spectroscopy. The examples in each chapter illustrate the text and may suggest other possible applications. They are mainly concerned with the spectroscopy of free atoms and molecules and are, of course, not complete, but have been selected from the literature or from our own laboratory work for didactic purposes and may not represent the priorities of publication dates. For a far more extensive survey of the latest publications in the broad field of laser spectroscopy, the reader is referred to the proceedings of various conferences on laser spectroscopy [1-11] and to textbooks or collections of articles on modem aspects of laser spectroscopy [12-32]. Since scientific achievements in laser physics have been pushed forward by a few pioneers, it is interesting to look back to the historical development and to the people who influenced it. Snch a personal view can be found in [33, 34]. The reference list at the end of the book might be helpful in finding more details of a special experiment or to dig deeper into theoretical and experimental aspects of each chapter. A useful Encyclopedia of spectroscopy [35, 36] gives a good survey on different aspects of laser speclroscopy. 

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