Vibronic energy

Figure 3. Low-energy vibronic spectrum in a. 11 electronic state of a linear triatomic molecule, computed for various values of the Renner parameter e and spin-orbit constant Aso (in cm ). The spectrum shown in the center of figure (e = —0.17, A o = —37cm ) corresponds to the A TT state of NCN [28,29]. The zero on the energy scale represents the minimum of the potential energy surface. Solid lines A = 0 vibronic levels dashed lines K = levels dash-dotted lines K = 1 levels dotted lines = 3 levels. Spin-vibronic levels are denoted by the value of the corresponding quantum number P P = Af - - E note that E is in this case spin quantum number),...

Figure 5. Low-energy vibronic spectrum in a 3 A electronic state of a linear triatomic molecule. The parameter c determines the magnitude of splitting of adiabatic bending potential curves, As0 is the spin-orbit coupling constant, which is assumed to be positive. The zero on the...

Figure 10. Low-energy vibronic levels in the X2II state of HCCS computed in various approximations [152]. Hq zeroth-order approximation (both vibronic and spin-orbit couplings neglected). Hi. vibronic coupling taken into account, spin-orbit interaction neglected. Hi + Hs0 both vibronic and spin-orbit couplings taken into account. Solid horizontal lines K = 0 vibronic levels dashed line K — 1 dash-dotted lines K = 2 dotted lines K — 3. Values of the quantum numbers V4, N of the basis functions dominating the vibronic wave function of the level in question are indicated. Approximate correlation of vibronic states computed in various approximations is indicated by thin lines. In all cases the stretching quantum numbers are assumed to be zero.

SUGGESTED EXPERIMENTS FOR THE CHARACTERIZATION OF THE LOW ENERGY VIBRONIC STRUCTURE... 

Benzene has a relatively low ionization potential (9.247 eV or 74580 cm ) so that all transitions from a2u and many from eig will lie beyond it and lead to super-excited states The second 1P ivas shown to belong to the highest filled o orbital It is not our intention to treat the spectrum of benzene in detail we merely used it as an example for the benefit of the non-initiated Reader as a simple MO + Rydberg scheme without energies, vibronic interactions, a electrons, and so on. Since the... 

To account for the low-energy vibronic structure of multi-mode E e systems, a cluster model has been introduced by O Brien et al. " This is an effective one-mode description which correctly reproduces the multi-mode stabilization energy, Eq. (16). For the description of multi-mode JT band shapes, on the other hand, another effective one-mode model is more appropriate, which may be called effective single-mode Hamiltonian. The idea consists in performing a rotation in normal-coordinate space such that the coupling terms, Eq. (15), are represented by a single mode in... 

The IR reflection spectra of the deposited films reveal that doping causes the appearance of low-energy vibronic transitions, much more intense than the corresponding IR bands of the undoped material as a consequence of the high dipole moments [76]. In the region from 1000 to 1500 cm", a strong interband absorption, due to free carriers, obscures the spectrum completely. In the 800-1600 cm" range, doped PP shows seven absorption bands [77] and doped PT is characterized by four bands [78]. 

It was found that the major features of the spectra at 300 K are the two sharp lines Rin, and R2m peaking at 680 nm and the broad, structured band peaking at lower energies. The latter is due the superposition of low-energy vibronic emission transitions from the components of the Eg level and emission from the relaxed excited state of the % level which is Stokes-shifted to lower energy compared to... 

The triple intersection of Eig. 6.7 deserves special mentioning with respect to low-energy vibronic motion. It has been pointed out above that the surface topology near a degeneracy (conical or not) is not of central importance for the strength of the nonadiabatic coupling effects. Eor low-energy motion this shape does matter. 

Figure 8. In this spectrum, only the K+ = 0 projections of even N+ are seen in the lower-energy vibronic component, whereas only those from odd N+ are seen in the higher-energy vibronic component. This effect can be attributed to nuclear spin statistics, and indicates unambiguously that the lower-energy vibronic component has B symmetry, and that the higher-energy vibronic component has B2g symmetry. Thus the rotational structure in the ZEKE spectrum has established that the B2g level in the quadratically split 6 (/ = 3/2) levels of the benzene cation, lies above the B g level.

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