Fine structure of hydrogen

For radiofrequency measurements of the fine structure of hydrogen, on the other hand, the Doppler effect is completely tmimportant, since it is proportional to the frequency which is actually measured. The fine structure intervals are given by frequency differences in optical spectroscopy in radiofrequency spectroscopy they are measured directly. The greater precision of radiofrequency measurements would compel careful investigation of the conditions in a gas discharge if this method were chosen for the excitation of the atoms. In fact, in the radio-frequency experiments which have so far been performed on hydrogen and ionized helium, the method of excitation by electron bombardment has been used. 

E. E. Salpeter. Mass Carreddons to the Fine Structure of Hydrogen-like Atoms. Phys. Rev., 87(2) (1952) 328-343. 

A more serious omission is that we have not discussed the application of any of these techniques to the study of the Lamb shift in hydrogenic systems and the fine structure of the light elements H, He, Li, etc. The development of our understanding of the fine structure of hydrogen-like and helium-like atoms is reported in the proceedings of the International Conferences on Atomic Physics which are published under the title Atomic Physics, Vols. 1-4. 

W. E. Lamb (Stanford) the fine structure of the hydrogen spectrum. 

This simplified treatment does not account for the fine-structure of the hydrogen spectrum. It has been shown by Dirac (22) that the assumption that the system conform to the principles of the quantum mechanics and of the theory of relativity leads to results which are to a first approximation equivalent to attributing to each electron a spin that is, a mechanical moment and a magnetic moment, and to assuming that the spin vector can take either one of two possible orientations in space. The existence of this spin of the electron had been previously deduced by Uhlenbeck and Goudsmit (23) from the empirical study of line spectra. This result is of particular importance for the problems of chemistry. 

Lamb, W.E., Retherford, R.C., 1947, Fine Structure of the Hydrogen Atom by a Microwave Method, Phys. Rev. 72, 241 Mandel, L., Wolf, R, 1995, Optical Coherence and Quantum Optics, Cambridge University Press Newton, 1952, Opticks, Dover... 

For pure WO3 the fine structure of the W(4f) peak shows considerable changes after reduction of the crystal. With the nonreduced stoichiometric crystal only two levels 4f7yj and 4f5/2 are observed, but after reduction the superposition of two doublets induces broadened features. Shifts due to the transformation of W to are revealed by a curve fitting procedure however, more drastic reduction can only be effected by hydrogen and argon ion-bombardment when W " " and W° states appear (Fig. 19). 

Woods V.L. Jr Method for characterization of the fine structure of protein binding sites employing amide hydrogen exchange. U.S. 

Fine structure. Evidently the set of term values is exactly the same as on the usual theory but the quantum numbers are different, making new transitions possible and changing the intensities of the fine structure. The hydrogen fine structiure is so obscured by the natural breadth of the lines that no information can be obtained from it, and we must turn to the spectrum of ionized helium. For Paschen s data the reader is referred to Sommerfeld, figures 89-92. The only measurements of value for the... 

But experiments to resolve the fine structure of the Balmer lines were difficult as you all know, resolution was impeded by the Doppler broadening of components. So ionized helium comes into the picture, because, as Sommerfeld s formula predicted, fine structure intervals are a function of (aZ)2, so in helium they are of order four times as wide as in hydrogen and one has more chance of resolving the Doppler-broadened lines. So PASCHEN [40], in 1916. undertook an extensive study of the He+ lines and in particular, 4686 A (n = 4->3). Fine structure, indeed, was found and matched against Sommerfeld s formula. The measurements were used to determine a value of a. But the structure did not really match the theory in that the quantum numbers bore no imprint of electron spin, so even the orbital properties - which dominated the intensity rules based on a correspondence with classical radiation theory - were wrongly associated with components, and the value of a derived from this first study was later abandoned. 

Schuster P (1978) The fine structure of the hydrogen bond. In Pullman B (ed) Perspectives in quantum chemistry and biochemistry, vol 2 Intermolecular interactions from diatomics to biopolymers. Chapt 4. John Wiley Sons, NY... 

The hydrogen atom is the simplest one in existence, and the only one for which essentially exact theoretical calculations can be made on the basis of the fairly well confirmed Coulomb law of interaction and the Dirac equation for the electron. Such refinements as the motion of the proton and the magnetic interaction with the spin of the proton are taken into account in rather approximate fashion. Nevertheless, the experimental situation at present is such that the observed spectrum of the hydrogen atom does not provide a very critical test either of the theory or of the Coulomb law of interaction between point charges. A critical test would be obtained from a measurement of the fine structure of the n = 2 quantum state. 

The influence of catalyst preparation on the surface properties of fine carbon black-supported platinum particles of similar size (4nm) was investigated. Different adsorption behavior was indicated by varying shapes and fine structures of the vibrational modes of the dissociatively adsorbed atomic hydrogen on these nanoparticles (58b). 

Less direct evidence for the position of the H atom also comes from proton magnetic resonance studies and from values of residual entropy. The positions of the protons in the H2O molecules in gypsum have been determined indirectly from the fine structure of the n.m.r, lines they are found to lie at a distance of 0-98 A from the 0 atom along an O-H-0 bond. For n.m.r. studies of a number of hydrates see p. 564 the method has also been used to locate the H atoms in Mg(0H)2 (p. 521). Measurements of residual entropy confirm the existence of two distinct locations for the proton in hydrogen bonds in ice (p. 539), salts of the type of KH2PO4, and Na2S04.10 H2O (which has residual entropy about two-tenths that of ice). 

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