Class I system

In Class I systems, the coupling is very weak, and there are essentially no electronic transitions. 

For class I systems, 0 = 0 and the mixed valence absorption bands observed generally fall at frequencies larger than 27 000 cm , except when the system contains a colored ion as a constituent. Intervalence interactions (see Intervalence Transfer Transition) can provide a source for intensification of such ligand field transitions, however, in class I systems. The mixed valence electronic transition is given by equation (2), where has the same meaning for the excited state as a does for the ground state. Hence a = /J = 0 for true class I behavior. 

As for symmetrical systems, the properties of an unsymmetrical Class I system are essentially those of the separate reactants. Although Class II systems are valence trapped, sufficiently endergonic reactions can exhibit a single minimum close to the non-interacting reactant minimum. This minimum shifts to = 0.5 only when Hah becomes very large. Provided that Hah < (>i + AG°)/2 and AG° < 2, the positions of the reactant and product minima are given by Eqs 19a and 19b, while the location of the transition state is given by Eq. 19c. 

The reference reaction in the case of Class I systems is the equilibrium reaction of the system under investigation and therefore offers the best possible comparison for determining a transition structure. For this reason the Leffler equation (Class I) is commonly used to indicate the structure of a transition state. 

Several classes of precursor complexes can be distinguished (see Table I), depending on the relative magnitudes of A and H g. The properties of class I systems are predominantly those of the separate components, and the electron transfer is nonadiabatic. Limiting class I behavior corresponds to the zero-interaction case discussed earlier. Class II systems possess new optical and electronic properties in addi-... 

For class I systems, a = 0 and the mixed valence absorption bands observed generally fall at frequencies larger than 27 000 cm except when the system contains a colored ion as a constituent. Intervalence interactions see Intervalence... 

The preceding expressions can be soived provided the composition of the exit stream is known. In many instances, it is acceptable to assume that the composition corresponds to saturation conditions systems in which this occurs are said to exhibit fast-growth or Class II behavior. Should growth kinetics be too slow to use essentially all the supersaturation (i.e., the solution concentration is greater than that at saturation), the system is said to exhibit slow-growth behavior and is classified as a Class I system. 

Two conclusions are apparent from Table 11.3-8. The first is that increasing hold time decreases crystal size, and the second is that the influence of this variable is not dramatic. At this point, a holding time r of 315 min is selected since additional reduction in holding time could result in loss of yield that is, the system may revert from a Class II system (no residual supersaturation in effluent liquor) to a Class I system (measurable supersaturation in exit liquor). 

The CANDU 6 incorporates comprehensive electrical systems that include Class IV, Class III, Class II and Class I systems, and redundancy and diversity to assure that all plant reliability and safety requirements are met. The Class III power system for example, includes four diesel generating sets, each capable of sustaining all necessary plant loads. 

ELECTRIC POWER SYSTEM Clas I,II and III Electnc System CSAB290 5 The Class III system pow ers designated safety -related and economic equipm i protection loads pump motors, valv es etc) Normally Class IV power supplies the Class III power W. cn the Class IV system fails two redundant standby diesel generators provide Class ni power The ac Class II and dc Class I systems supply un-mtermptible power to the control and safety svstems... 

Class I Class I system is the 220V DC power supply from batteries. This is... 

For mixed-valence bimetallic systems, Robin and Day distinguished three classes depending on the amount of metal-to-metal interaction [17]. Figure 6 is a plot of nuclear configuration vs. energy for the three classes of mixed-valence compounds. If there is essentially no interaction between the metal centers, it is called a class I system. Compounds of this type have properties that are a simple combination of Ihe properties of the two independent metal centers. Class I compounds do not exhibit IT transitions. Mixed-valence compounds that have some limited degree of interaction between the metal centers are considered to be class n. Class n systems still have a localized valency and can be described as... 

The argon-krypton reference system is a class I system with no azeotrope,and argon is the more volatile component. If a dipole moment is now added to the argon component, so that the mixture... 

The decrease in solute mass concentration Apt (= Mj) along an MSMPR crystallizer depends on a number of quantities, as one can see from relations (6.4.18) and (6.4.25). If the extent of supersaturation in product stream 1 is not exhausted, the system is identified as a class I system with a nonhigh yield. For class II systems, the supersaturation is... 

Class I systems, having 2.5-inch hose connections, are to be used by fire-fighting personnel only. 

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