Excited state, atomic

There is another approach which can be used in suitable circumstances. Developed by Kowalik and Kruger (31), it involves measuring the population of an excited atomic state by LIFS. If the ground state population is known to be uniform in the flow field, then information about temperature can be inferred. They have used the method to measure electron number density in MHD plasma flows. 

The potential of the SW approach to systematize inneratomic properties and processes can be easily illustrated by reconsidering chemically induced nuclear lifetime variations which, among others, are of relevance to the calibration problem of Moessbauer isomer shifts. Highly excited atom states carrying single or multiple vacancies in inner shells form another promising subject of SW simulations. In the latter case the results of a DV-Xa study of the K-shell x-ray satellite intensities of metal fluorides can be used for a comparative assessment of both methods. 

Creation and decay of highly excited atom states carrying inner-shell vacancies... 

The first quantitative measurement of the distribution of excited atomic states produced in the multiphoton dissociation of a metal carbonyl has been made for Cr(CO)6. Photodissociation does not yield spin- or parity-differentiated states, rather the state distribution appears to be statistical. Photofragmentation dynamics of Cr(CO)6 in the gas phase have been measured and two channels of dissociation revealed. One of these is a rapid predissociation (efficiency 36%) and the other a slow process (efficiency... 

We see that a measurement of the asymmetry of a scattered polarised beam or the polarisation after scattering of an initially-polarised beam yields directly the orientation (Lx) of the excited atomic state. This is usually obtained by coincidence experiments (chapter 8). The above case is, however, a special case and in more complicated situations the two techniques yield complementary information. 

In the model Hamiltonian (34), the excited atomic state is specified by the following three orthogonal states ... 

For the electric dipole radiation described by the Jaynes-Cummings Hamiltonian (34), the polarization of photons at kr > 0 is defined by the quantum number m = 0, 1, describing the excited atomic state. 

In Section III.B, we introduced the atomic quantum phase states through the use of the representation of the SU(2) algebra (37) and dual representation (48), corresponding to the angular momentum of the excited atomic state. The multipole radiation emitted by atoms carries the angular momentum of the excited atomic state and can also be specified by the angular momentum [2,26,27], The bare operators of the angular momentum of the electric dipole... 

Since the atomic SU(2) quantum phase, discussed in Section III.B, is defined by the angular momentum of the excited atomic state, the conservation law (62) can be used to determine the field counterpart of the exponential of the phase operator (41) and other operators referred to the SU(2) quantum phase [36,46], For example, it is easily seen that the operator... 

One of the major trends of current research is the study of transmission of information between the atom and photons in the process of emission and absorption. In particular, the conservation of angular momentum provides the transmission of the quantum phase information in the atom-held system. The atomic quantum phase can be constructed as the 57/(2) phase of the angular momentum of the excited atomic state (Section III). It is shown that this phase has very close connection with the EPR paradox and entangled states in general. Via the integrals of motion, it is mapped into the Hilbert space of multipole photons (Section IV.A). This mapping is adequately described by the dual representation of multipole photons, constructed in another study [46] (see also Section IV.B, below). Instead of the quantum number m, corresponding to the... 

Converting the absorption lines into abundances requires knowledge of line positions of neutral and ionized atoms, as well as their transition probabilities and lifetimes of the excited atomic states. In addition, a model of the solar atmosphere is needed. In the past years, atomic properties have seen many experimental updates, especially for the rare earth elements (see below). Older solar atmospheric models used local thermodynamic equilibrium (LTE) to describe the population of the quantum states of neutral and ionized atoms and molecules according to the Boltzmann and Saha equations. However, the ionization and excitation temperatures describing the state of the gas in a photospheric layer may not be identical as required for LTE. Models that include the deviations from LTE (=non-LTE) are used more frequently, and deviations from LTE are modeled by including treatments for radiative and collision processes (see, e.g., [27,28]). 

The problem is to calculate all molecular states leading to a given excited atomic state, and find out whether one or more of these are crossing the ground state. If all potential curves involved and the molecular wave-functions in the region of interaction are known, the transition probability between the states can be calculated by various models. A number of excellent reviews exist on this subject,1011-1218-22 and so it will not be discussed here. For a short comprehensive discussion the reader is referred to the article on collisional ionization in this volume.118... 

Ambartzumian, R. V. Furzikov, N. P. Letokhov, V. S. and Puretsky, A.A., "Measuring Photoionization Cross-Sections of Excited Atomic States," Appl. Phys., 1976, 9, 335-337. 

Excited atomic states in hydrogen can be produced by electron bombardment of molecular or of atomic hydrogen. Lamb and Retherford used the latter method (see Chapter VIII), since their method of observing radiofrequenoy resonances relied on the detection of the atoms themselves, which were produced as a beam. The relative merits of various ways of breaking down the molecule are described in one of their papers [82], Lamb and Sanders, who investigated a different excited state (section 10.2.2), detected radiofrequenoy reson-... 

In fact, the NEET is a fundamental but rare mode of decay of an excited atomic state in which the energy of atomic excitation is transferred to the nucleus via a virtual photon. This process is naturally possible if within the electron shell there exists an electronic transition close in energy and coinciding in type with nuclear one. In fact, the resonance condition between the energy of nuclear transition wn and the energy of the atomic transition coa should be fulfilled. Obviously, the NEET process corresponds to time-reversed bound-state internal conversion. Correspondingly, the NEEC process is the time-reversed process of internal conversion. Here, a free electron is captured into a bound atomic shell with the simultaneous excitation of the nucleus. 

The fundamental parameter of the cooperative NEET process is a probability NEET (cross section) of the nuclear excitation by electron transition. In fact, it can be defined as the probability that the decay of the initial excited atomic state will result to the excitation of and subsequent decay from the corresponding nuclear state. Within the energy approach, the decay probability is connected with an imaginary part of energy shift for the system (nuclear subsystem plus electron subsystem) excited state. An imaginary part of the excited state / energy shift in the lowest PT order can be in general form written as [18,26]... 

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