Fragment charge difference method

We discuss the FCD method for hole transfer a generalization to other cases of charge transfer is straightforward [41]. The (real) diabatic wave functions and (j)a are assumed to be normalized and completely localized on donor and acceptor, respectively. Furthermore, the adiabatic states ij/i and ij/z of the 

Finally, we mention a simplified FCD (SFCD) expression for the two-state model, where Eq. 15 is reduced to [41] 

If donor and acceptor are in resonance, Aqi=Aq2=0 in Eq. 15 or Aq=0 in Eq. 16, then both FCD expressions reduce to Eq. 7. Also, when considering a CT system, it is often informative to estimate the energy gap Eg-Ed between the diabatic donor and acceptor states. From Eq. 9, one directly obtains 

If donor and acceptor states are degenerate, = then cos2ft)=0 and, therefore, sin2 =l then, in line with Eq. 10, the electronic coupling is determined by half of the adiabatic energy splitting, Eq. 7. 

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Thermally weighted Franck-Condon factor Fragment charge difference (method)... 

Similarly to the GMH method, the fragment charge difference (FCD) method yields a donor to acceptor coupling [42] ... 

Mass spectroscopy is increasingly being used to resolve amino acid sequences due to recent developments in this technique. There are several different methods that can be used, but basically this method determines the mass-to-charge ratio of individual amino acids of a fragmented protein. The pattern of fragmentation can be extremely complex, but peptide bonds are mostly broken to cause the fragmentation. The patterns of fragmentation are known, and this allows the sequence to be determined. 

In almost all the works, cited above, the separation of the molecular system in fragments to treat them with different methods is made based on chemical intuition without attempts to give sufficient theoretical foundation of such treatment. As shown in Sections I and II, the intuitive approach may lack some important elements of the phenomenon. Also one of the most significant features important to the modeling of TMS, the QM-MM charge transfer, is not considered in these works. 

In its simplest form, a mass spectrometer is an instmment that measures the mass-to-charge ratios ml of ions formed when a sample is ionized by one of a number of different ionization methods (1). If some of the sample molecules are singly ionized and reach the ion detector without fragmenting, then the ml ratio of these ions gives a direct measurement of the molecular weight. The first instmment for positive ray analysis was built by Thompson (2) in 1913 to show the existence of isotopic forms of the stable elements. Later, mass spectrometers were used for precision measurements of ionic mass and abundances (3,4). 

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