Pair States

We are now well prepared to calculate the localized modes in the presence of two particles 1 and 2. We construct them from normalized electric and magnetic modes s= 1,2 localized at the individual particles 7=1,2. In the case of spheres we put 

The mutual inversion of coordinates at spheres 1 and 2 entails accounting for the rotational symmetry by coupling inverted spherical harmonics P cos9i) exp in(pi) and P (cos92)exp(-i7 j()2). Normalization of all modes used is obtained if we require the normal components of all fields to vanish on the surface of a perfectly reflecting cavity with radius r, yielding 

By transposing all modes to a single sphere i by means of addition theorem (5.36) and satisfying boundary condition (5.23) we obtain 

Conditions (5.42), (5.43) fully determine the amplitudes and frequencies of the localized electromagnetic modes in the presence of two spheres 1 and 2. We have built up Z r) at each sphere 1 and 2 from ingoing and 

Similarly, to find the pair states in the presence of two cylinders 1 and 2 we put 

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The association constant of the lcCM counts all paired states of oppositely charged ions in the range a[Pg.467]

Another important factor to determine the charge separation efficiency is the distance between and the mutual orientation of the donor and the acceptor in the geminate ion-pair state. The rate of charge recombination depends on whether... 

The reaction exothermicities ( —AG°) for forward and back ET in polar media were approximately estimated to be 1.39 and 2.18 eV, respectively [120], Since the back ET is highly exothermic, the relatively small kb-1 values for the compartmentalized system may be ascribed to the combined effect of the inverted region [97-99] and the loose ion-pair state. 

EL), conjugated polymers are also of interest as materials for optically or electrically pumped stimulated emission. For effects of this type, the ratio of stimulated emission to photoinduced absorption (PA) is of particular interest for conjugated polymers. In this context, the orign of the PA is controversial the PA can be a result of the formation of either charge-separated polaron pair -states or excimers. Initial experiments support the conjecture that LPPP 26 is significantly superior [49], as the stimulated emission of LPPP 26 is markedly more intense than that of PPV under comparable conditions. 

This is called [35] Mixed Pair State approximation (MRS). The name, which probably is not the best one, refers to the fact that the nj, barring exceptions, has a value smaller than one, which means that the electron pair is not in the pure state I. 

It has been suggested that P BChl (where BChl is one of the two monomeric or "accessory BChls that are not part of P) is a transient state prior to P "I (14,16,19), although the evidence supporting this view has been criticized (23, 24) Recent subpicosecond studies find no evidence for P "BChl (8,9) These new results do not preclude some involvement of a monomeric BChl in the early photochemistry, only that P BChl apparently is not a kinetically resolved transient state Perhaps P itself contains some charge-transfer character between its component BChls, or between P and one or both of the monomeric BChls (8,9,25-27) One of the two monomeric BChls apparently can be removed by treatment of the reaction center with sodium borohydride (28) and subsequent chromatography, with no impairment of the primary electron transfer reactions (29) Thus, at present it appears that P I is the first resolved radical-pair state, and it forms with a time constant of about 4 ps in Rps sphaeroides ... 

The primary process following a photoexcitation of nltrosamldes XIV Is the dissociation of the N-N bond to form a radical pair XV and the ensuing chemical events are the reactions of amldyl and nitric oxide radicals In the paired state or Individually In the bulk of solutions. Naturally, secondary reactions, thermal or photolytic, have to be taken Into consideration under Irradiation conditions (21). First of all, the relatively straightforward chemistry of selective excitation In the n-ir transition band (>400 nm) will be discussed, followed by the chemistry of Irradiation with a Pyrex filter (>280 nm). As nitric oxide Is known to be rather unreactlve (23), primary chemical processes In the Irradiation with >400 nm light under... 

Free radical A reactive species having an unpaired electron that initiates a reaction with a double bond, for example, in acrylate polymerization. It is produced from its stable paired state by energy absorption. 

When irradiated, Oj is excited to the singlet spin-paired state... 

Materials which contain electrons in paired states and exhibit weak negative (about 10-6) susceptibilities (they are pushed out of a magnetic field). 

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