Multiple states

Multiple state emission and related phenomena in transition metal complexes. M. K. DeArmond and C. M. Carlin, Coord. Chem. Rev., 1981, 36, 325-355 (89). 

Chattoraj M, King BA, Bublitz GU, Boxer SG (1996) Ultra-fast excited state dynamics in green fluorescent protein multiple states and proton transfer. Proc Natl Acad Sci USA 93 8362-8367... 

Transition-matrix estimators are typically more accurate than their histogram counterparts [25,26,46], and they offer greater flexibility in accumulating simulation data from multiple state conditions. This statistical improvement over histograms is likely due to the local nature of transition probabilities, which are more readily equilibrated than global measures such as histograms [25], Fenwick and Escobedo... 

Chattoraj, M., King, B. A., Bublitz, G. U. and Boxer, S. G. (1996). Ultrafast excited state dynamics in green fluorescent protein Multiple states and proton transfer. Proc. Natl. Acad. Sci. USA 93, 8362-7. 

Theories of electron mobility are intimately related to the state of the electron in the fluid. The latter not only depends on molecular and liquid structure, it is also circumstantially influenced by temperature, density, pressure, and so forth. Moreover, the electron can simultaneously exist in multiple states of quite different quantum character, between which equilibrium transitions are possible. Therefore, there is no unique theory that will explain electron mobilities in different substances under different conditions. Conversely, given a set of experimental parameters, it is usually possible to construct a theoretical model that will be consistent with known experiments. Rather different physical pictures have thus emerged for high-, intermediate- and low-mobility liquids. In this section, we will first describe some general theoretical concepts. Following that, a detailed discussion will be presented in the subsequent subsections of specific theoretical models that have been found to be useful in low- and intermediate-mobility hydrocarbon liquids. 

Renner-Teller effect, multiple-state systems, 623... 

Which of the possible multiple states actually occurs in steady-state operation ... 

Within its orbit, which has some of the characteristics of a molecular orbital because it is shared with electrons on the surrounding atoms, the electron has two possible spin multiplicity states. These have different energies, and because of the spin-multiplicity rule, when an (N-V) center emits a photon, the transition is allowed from one of these and forbidden from the other. Moreover, the electron can be flipped from one state to another by using low-energy radio-frequency irradiation. Irradiation with an appropriate laser wavelength will excite the electron and as it returns to the ground state will emit fluorescent radiation. The intensity of the emitted photon beam will depend upon the spin state, which can be changed at will by radio-frequency input. These color centers are under active exploration for use as components for the realization of quantum computers. 

Hydrogen adsorption and oxidation of formic acid show a pronounced dependence on the structure of single crystal surfaces. The influence of the terrace and step orientation and step density is reflected in both reactions on step surfaces. The multiple states of hydrogen adsorption can be correlated with the nature of adsorption sites. 

R. W. Harrigan, G. D. Hager, and G. A. Crosby, Evidence for multiple-state emission from ruthenium(II) complexes, Chem. Phys. Lett. 21, 487-490(1973). 

Thermodynamic Consequences of Multiple States Changes in Phase Equilibria Directly Attributable to Interaction with External Magnetic Fields... 

One of the consequences of accepting the presence of multiple magnetic states is an additional contribution to the entropy and, therefore, several authors have considered the inclusion of multiple states in their description of low-temperature phase transformations in Fe and its alloys (Kaufman et al. 1963, Miodownik 1970, Bendick and Pepperhoff 1978). However, most authors have, in the end, preferred to describe the magnetic effects in Fe using more conventional temperature-independent values for the magnetic moments of the relevant phases. This is partly linked to the absence of any provision for the necessary formalism in current... 

In a detailed study of the equilibria involved in the urea transition, Tanford (354) showed that a two-state process could not explain the RNase data and that the cooperative units, whose unfolding was reflected in the measurements, must be much less than the total molecule. Each unit was probably not more than one-third of the total molecule. This conclusion was based on Tanford s theory and the data of Nelson and Hummel (351) and of Foss and Schellman (355). The midpoint of the transition at room temperature in 0.1 M KC1 and neutral pH is about 6 M urea. Barnard (356) found a midpoint at 6.7 M urea at pH 7 and 25°C. By fluorescence the midpoint was about 6.5 M urea (308). Between 12 and 16 molecules of urea per molecule of protein appeared to be involved in the transition (356), 12 being the kinetic order of the unfolding reaction and 16 being the value derived from the slope of the equilibrium curve. Again evidence for multiple states was presented. 

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