Ground states multiple

Flash photolysis studies<22) have indicated singlet methylene to be produced from the diazomethane-excited singlet upon loss of nitrogen followed by collisional deactivation to the triplet, the ground state multiplicity for this molecule. 

The first-row homonuclear diatomic molecules A2 of main-group elements (A = B, C, N, O, F) exhibit a well-known diversity of ground-state multiplicities, bond lengths, and bond energies. Calculated potential-energy curves for low-lying singlet and triplet states of these species are pictured in Fig. 3.27 and summarized in Table 3.13 (with comparison experimental values). Because these homonuclear... 

Let us also briefly examine the corresponding behavior in second- and third-row homonuclear diatomics. Figures 3.31(a) and (b) display the calculated potential-energy curves for these species (ground-state multiplicities only) and Table 3.16 summarizes the equilibrium bond lengths and bond energies. 

There is another important feature to note in the curve of Figure 10.1, the second derivative of the energy with respect to Ns is discontinuous at the ground state multiplicity and must be negative in both directions, due to the fact that both branches in the plot have negative curvatures. This second derivative, as in the... 

Ion Configuration Ljof ground state (multiplicity in parentheses) gj... 

Infrared spectroscopical data encode a lot of structural information and can be analyzed with the help of computational methods (vide supra) aiding in the identification of the observed species. Sometimes, two different electronic states may lie very close in energy and have similar geometries. In such cases (e.g., the quinonoid radicals to be described in Section II.B.), the predicted differences in the IR spectra are too small to allow an unambiguous assignment of the ground-state multiplicity. In this respect, ESR spectroscopy provides valuable comple-... 

The IR spectra of 43, 47, and 53 cannot be used alone for predicting the ground-state multiplicity, because of the similarity between the A and A states. However, the computational results in conjunction with the low temperature used in the experiments and the lack of ESR signals when 47 was generated were interpreted in favor of singlet biradical ground states [108]. 

Curie s Law and Its Application to Assignments of the Ground-State Multiplicity... 

Although carbenes have two electronic states of different stability, it is not always the ground-state multiplicity that is involved in the reaction. What are then factors that control the reaction pattern of carbenes ... 

G(d) levels. At the B3LYP /6-31G(d) level, 21 was found to be more stable than 41 by 10.2 kcal mol-1. Therefore, a ground-state multiplicity cannot be assigned with certainty from the results of these calculations. 

Excimer-forming complexes (GS = the ground state) Multiplicity of excimer Solvent Formation (K) and decay rate (k, in s ) constants Ref. 

Assumed bond lengths (A) RCR O Ground-state multiplicity... 

In order to compare the T-, parameters of Judd-Ofelt theory for different lanthanides, Camell et al. [99] have removed the dependence of Tk on the ground state multiplicity (27 + 1) and defined a new set of parameters, T given by... 

Nash, J. J. Dowd, P Jordan, K. D. Theoretical study of the low-lying triplet and singlet states of diradicals prediction of ground-state multiplicities in cyclic analogs of tetramethyleneethane, 7. Am. Chem. Soc. 1992,114, 10071-10072. 

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