Atom, electronic transitions

Arrange the following H atom electron transitions in order of increasing frequency of the photon absorbed or emitted ... 

Making use of the SEFS formula obtained [Eq. (38)] and the estimates of the atomic electron transition intensities [Eqs. (70), (78)], we calculate the temperature behavior of the Fe, Ni, and Cu MW SEFS spectra and compare the obtained results with the experimental data. 

The electron transitions are assumed to follow the dipole selection rules, and the transitions with a decrease in the orbital quantum number are ignored in Eq. (101). Hereinafter, to simplify the calculation we consider that 28 = 252. This approximation is not too rough, since the difference between 28 and 25° is insignificant. Estimates of the intensities of atomic electron transitions in processes of first order [dJ p Ep, p), Eq. (70)] and second order [dJ p Ep, p), Eq. (86)] have been made in the preceding section, and their relative intensity is given by the parameter HanpC = nanp 6/ aQa) ] /a, depending on the number of valence and core electrons and the inverse radii of localization of their wave functions. When... 

A. Gallagher, T. Holstein, Collision-induced absorption in atomic electronic transitions. Phys. Rev. A 16, 2413 (1977)... 

X-ray Electromagnetic radiation of wave length c. 1 k. X-rays are generated in various ways, including the bombarding of solids with electrons, when they are emitted as a result of electron transitions in the inner orbits of the atoms bombarded. Each element has a characteristic X-ray spectrum. 

There are two basic physical phenomena which govern atomic collisions in the keV range. First, repulsive interatomic interactions, described by the laws of classical mechanics, control the scattering and recoiling trajectories. Second, electronic transition probabilities, described by the laws of quantum mechanics, control the ion-surface charge exchange process. 

For electronic transitions in electron-atom and heavy-particle collisions at high unpact energies, the major contribution to inelastic cross sections arises from scattering in the forward direction. The trajectories implicit in the action phases and set of coupled equations can be taken as rectilinear. The integral representation... 

Reference has already been made to the high melting point, boiling point and strength of transition metals, and this has been attributed to high valency electron-atom ratios. Transition metals quite readily form alloys with each other, and with non-transition metals in some of these alloys, definite intermetallic compounds appear (for example CuZn, CoZn3, Cu3,Sng, Ag5Al3) and in these the formulae correspond to certain definite electron-atom ratios. 

The one exception to this is the INDO/S method, which is also called ZINDO. This method was designed to describe electronic transitions, particularly those involving transition metal atoms. ZINDO is used to describe electronic excited-state energies and often transition probabilities as well. 

Whereas the gas lasers described use energy levels characteristic of individual atoms or ions, laser operation can also employ molecular energy levels. Molecular levels may correspond to vibrations and rotations, in contrast to the electronic energy levels of atomic and ionic species. The energies associated with vibrations and rotations tend to be lower than those of electronic transitions thus the output wavelengths of the molecular lasers tend to He farther into the infrared. 

AIterna.tives to y-Ray Emission. y-Ray emission results ia the deexcitation of an excited nuclear state to a lower state ia the same nucHde, ie, no change ia Z or. There are two other processes by which this transition can take place without the emission of a y-ray of this energy. These are internal conversion and internal pair formation. The internal-conversion process iavolves the transfer of the energy to an atomic electron. 

---