4. Properties of Atoms

Publisher Summary This chapter discusses the properties of atoms. The chapter deals with the methods of obtaining, observing, detecting, and analyzing the spectra of atoms in the optical region. The best presently developed means of measuring wavelength in this region are much more accurate than those of measuring intensity. Polarization is considered mainly in connection with methods of observing and analyzing the transverse Zeeman effect where the chapter deal with two orthogonal plane polarizations. Finally, only a brief mention is given of the techniques for studying light sources which vary in brightness with time, that is, of time-resolved spectroscopy. A further limitation of the chapter is that it will be confined to the experimental methods of optical atomic spectroscopy. Any source of radiation in the “optical” regions can be considered a potential source for spectroscopic studies. Sources of continuous radiation find their principal application as sources of background against which discrete or sometimes continuous absorptions can be measured. The ideal source for this application would have constant intensity structureless spectral distribution over the region of the spectrum under study, and zero intensity elsewhere.