Spectra of foreign atoms

SPECTRA OF FOREIGN ATOMS IN LIQUID HELIUM CURRENT THEORETICAL UNDERSTANDING... 

A systematic approach which gives a simple interpretation of the spectral line shifts and of other structural properties of spectra of foreign atoms surrounded by liquid helium has been presented. Results for hydrogen and helium atoms show that the qualitative behaviour of the calculated spectral properties agrees with experimentally available data. No specific experimen-... 

Spectra of foreign atoms in liquid helium Current theoretical understanding 393... 

The metastablity of antiprotonic helium is known to be affected when foreign atoms and molecules are added to the helium media, as revealed from delayed annihilation time spectra (DATS) in the early stage [2,24,25], However, DATS alone is a macroscopic quantity in which all the microscopic informations cannot be differentiated. Laser resonance techniques have made it possible to investigate microscopically the (n, /[-dependent lifetime shortening effects on the surrounding physico-chemical conditions of antiprotonic helium. 

Here we conclude our account of Bohr s theory. Although it has led to an enormous advance in our knowledge of the atom, and in particular of the laws of line spectra, it involves many difficulties of principle. At the very outset, the fundamental assumption of the validity of Bohr s frequency condition amounts to a. direct and unexplained contradiction of the laws of the classical theory. Again, the purely formal quantisation rule, which stands at the head of the theory, is a foreign element which in the first instance is absolutely unintelligible from the physical point of view. We shall see later how both of these difficulties are removed in a perfectly natural way in wave mechanics. 

In 1938 Tsuchida devised a method for measuring the absorption spectra of crystals by combining a microscope and a spectrograph (48). This method was later used by him and his co-workers for measuring the dichroism of crystals (49). In 1939 Tsuchida further proposed a theory that the electron pairs used for coordinate bonds and the unshared electron pairs of the central metal atom are distributed in a symmetrical way around the central metal (50,57). This idea antedated the similar theory proposed in 1940 by Sidgwick and Powell (52), but Tsuchida s works were not known to foreign chemists because of war. 

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