Herzberg diagrams

Franck-Condon factors. The most common angular momentum coupling cases are discussed, and rotational fine structure in electronic transitions (cf. Fig. 4.3) is rationalized for heteronuclear and homonuclear diatomics using Herzberg diagrams. 

Figure 4.22 Herzberg diagram for allowed rotational transitions accompanying a -+ electronic transition in a heteronuclear diatomic molecule.

Fig. 4.25), all three rotational branches appear. Note that the P(l) and Q(0) lines are absent, since the J = 0 level cannot occur in a H state. A wealth of additional Herzberg diagrams may be found in G. Herzberg s classic Spectra of Diatomic Molecules [10]. 

Figure 4.24 Allowed rotational transitions in a Zg Z,t electronic transition in a heteronuclear diatomic molecule. Such Herzberg diagrams automatically incorporate the Laporte g u selection rule, since no allowed rotational transitions can be drawn for a Zg Zg or a Z Z electronic transition.

The Na2 fluorescence spectra in Fig. 4.26 are excellent examples of the rotational selection rules predicted by the Herzberg diagram in Fig. 

FIGURE 3.3 Schematic diagram of energy levels involved in HCI vibration-rotation transitions at room temperature (from Herzberg, 1950). 

The energy diagram describing NaCl dissociation is quite different to that observed for R—X and [R—X] dissociation. This is because for NaCl the two relevant configuration curves cross (Herzberg, 1950 Levine and Bernstein, 1974), in contrast to the situation for R—X and (R—X) where the two curves are separated. The well-known NaCl curve crossing is illustrated in Fig. 7. At infinite separation Na Cl is more stable than... 

Fig. V-8. Energy level diagram of CO A-X, fourth positive B-A, Angstrom C-A, Herzberg B-X, Hoptield Birge a-X, Cameron d-a, triplet e-a. Merman b-a, third positive c-a, 3A bands a -a, Asundi. The 1470 A line is in coincidence with the

Fig. 5. Ribbon diagram of TnC (from Herzberg and James, 1985). The structural C-terminal lobe (consisting of alpha helices E, F, G, and H in domains III and IV) has higher affinity for Ca2+ ions than does the regulatory N-terminal lobe (consisting of alpha helices A, B, C, and D in domains I and II). The D/E linker between the two lobes is often flexible, but when ordered it adopts an a-helical conformation with three turns fully exposed to solvent (see text).

The energy level diagram given in Figure 10 is one in which Herzberg s diagram66 is modified according to the more recent value of 11.1 e.v. for the dissociation limit. 

Calculations on triatomic molecules, because of their theoretical and experimental significance, will be mentioned below in some detail. Herzberg s Polyatomics [6] gives diagrams of the correlation of orbitals between large and small internuclear distances in linear AH2 molecules and in linear ABa molecules [6]. Walsh, in a classic series of papers [97], gave correlations of molecular orbitals between linear and bent AH2 molecules and linear and... 

A Walsh diagram for the correlation of orbitals between nonplanar and planar XH3 is depicted in Herzberg [6]. 

Fig. 5. Energy level diagram for Pd(2-thpy)2 dissolved in n-octane. The Tj state at 18,418 cm is zero-field split on the order of 0.2 cm. The emission decay times refer to the individual triplet suhstates I, II, and III, respectively, at T = 1.3 K. (Compare Fig. 6.) These suhstates are radiatively deactivated as purely electronic transitions, as well as by Franck-Condon (FC) and Herzberg-Teller (HT) vibrational activity, respectively. This leads the different vibrational satellites. (Compare also Sects. 4.2.2 and 4.2.3.) The lifetime of the S, state is determined from the homogeneous linewidth of the spectrally resolved Sq —> S, electronic origin. (Sect. 3.2) The electronic state at 24.7 x 10 cm is not yet assigned...

Fig. 26. Energy level diagram for the triplet sublevels of (a) perprotonated, (b) partially deu-terated, and (c) perdeuterated Pt(2-thpy)2 dissolved in an n-octane matrix (Shpol skii matrix). Emission decay times and spin-lattice relaxation times are given for T= 1.3 K. Several vibrational satellites are specified, HT = Herzberg-Teller active vibration, FC = Franck-Condon active vibration. The emission spectrum of the partially deuterated compound (b) exhibits vibrational satellites of the two different ligands. (Compare Fig. 27b.) The data given for Pt(2-thpy-hg)(2-thpy-d6) (b) refer to the lower lying site A. (Compare Ref. [23])...

Figure 3. Ribbon diagram of the Leu76 region of the TEM-1 (Jelsch et al., 1993), S. aureus (Herzberg, 1991) andB. licheniformis (Knox and Moews, 1991) structures. For simplicity, only those residues that are hydrophobic in TEM-1 and hydrophilic in the S. aureus or B. licheniformis structures are shown. Figure prepared with MOLSCRIPT (Kraulis, 1991) (Figure adapted from Huang et al., 1996).

Figure 2.1.b. Schematic diagram of the energy levels and vibration-rotation transitions (after Herzberg, 1950). The lower lines (v/ = 0) correspond to the fundamental vibrational state with different rotational states (J// = 0,1, 2,3,4). The first vibrationally excited state (v/ = 1) with related rotational states (J/ = 0 to 4) are shown by the upper lines. The transitions corresponding to the P and R branches are indicated. Transition AJ = 0 is not allowed in the case of the idealized rigid rotor, harmonic oscillator for a linear molecule, but can be observed (Q-branch) in other cases. The notations are from Herzberg (1950). 

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