Resonance intensity spectra

Figure 5.4 Resonance Raman spectrum of [Au2(dcpm)2](CI04)2 in acetonitrile solution at room temperature taken with 282.4 nm excitation, after intensity corrections and subtractions of the Rayleigh line, glass bands, and solvent bands. Reproduced with permission from [7a]. Copyright (1999) American Chemical Society.

It can be seen from Figures 3.7 and 3.8 that the calculations reproduce very well not only the experimental spectra but also the experimentally observed isotopic shifts indicating a high reliability of the computational method. According to this comparison, definite attribution can be made for even the difficult Raman bands that cannot be assigned based solely on the experimental results. It is, however, necessary to mention at this point that the calculated Raman spectrum provided directly by the ab initio computations correspond to the normal Raman spectrum with the band intensity determined by the polarizability of the correlating vibration. Since the intensity pattern exhibited by the experimentally recorded resonance Raman spectrum is due to the resonance enhancement effect of a particular chromophore, with no consideration of this effect, the calculated intensity pattern may, in many... 

If the "localized" formulation of the structure of Ru(bpy)3 as Ru(III)(bpy)2(bpy ) + is realistic, the resonance Raman spectrum of Ru(bpy)3+ can be predicted. A set of seven prominent symmetric modes should be observed at approximately the frequencies seen in Ru(III)(bpy)3, with approximately two thirds of the intensity of the ground state bpy modes. The intensity of the isolated 1609 cm - peak fits this prediction, as do the other "unshifted" peaks. A second set of seven prominent Raman modes at frequencies approximating those of bpy should also be observed. Figure 6 shows that this prediction is correct. The seven Ru(bpy)3+ peaks which show substantial (average 60 cm l) shifts from the ground state frequencies may be correlated one-for-one with peaks of Li+(bpy ) with an average deviation of 10 cm. In addition, the weak 1370 cm l mode in Ru(bpy)3 is correlated with a bpy mode at 1351 cnfl. It is somewhat uncertain whether the 1486 cm l bpy mode should be correlated with the Ru(bpy)3 mode at 1500 cm -1- or 1482 cm 1. It appears clear that the proper formulation of Ru(bpy)3 is Ru(III)(bpy)2(bpy ). This conclusion requires reinterpretation of a large volume of photophysical data (43,45,51 and references therein). 

Fig. 9.15 A ring resonator sensor interrogation circuits with (a) one bus waveguide, and (b) two bus waveguides. The plots give a qualitative indication of the typical intensity spectrum that would be observed at the respective output ports...

When one resonance in an NMR spectrum is perturbed by saturation or inversion, the net intensities of other resonances in the spectrum may change. This phenomenon is called the nuclear Overhauser effect (NOE). The change in resonance intensities is caused by spins close in space to those directly affected by the perturbation. In an ideal NOE experiment, the target resonance is completely saturated by selected irradiation, while all other signals are completely unaffected. An NOE study of a rigid molecule or molecular residue often gives both structural and conformational information, whereas for highly flexible molecules or residues NOE studies are less useful. 

Within 25 psec of electronic excitation the resonance Raman spectrum of Ni(OEP) in piperidine indicates an increase in the amount of 4-coordinate Ni(OEP) and loss of the piperidine ligands. Evidence for this is found in the increase in intensity of the band for 4-coordinate Ni(OEP) ( 1654 cm" ) relative to... 

Fig. 2. 245 -nm excited resonance Raman spectrum of (A) 0.225 mM Craq002 + and (B) 50 pM Craq1801802 + in 0.02 M HC104 at 0°C. Negative peaks arise from subtraction of the intense 4 bands at 934 and 629 cm-1. The asterisk indicates a burned spot on the intensifier of the diode-array detector. Reproduced with permission from J. Am. Chem. Soc. 1995, 117, 6483-6488. Copyright 1995 American Chemical Society. 

The N//-azaindole 40 with X = 6 is paramagnetic. Its electron spin resonance (ESR) spectrum (in DMSO) shows a characteristic triplet with a 1 1 1 intensity and the hyperfine splitting constant An = 16.04 Oe. 

The metal coordination environment for HPP dioxygenase appears to be an exception to the 2-His-l-Asp active site discussed. This enzyme is isolated in the high-spin Fe(III) state as indicated by an intense EPR signal at g = 4.3. More significantly, it is deep blue in color (A,max 595 nm) and exhibits a resonance Raman spectrum characteristic of a tyrosinate ligand [219], Indeed, sequence comparisons of seven HPP dioxygenases from various mammalian and pseudomonad sources indicate the presence of a conserved Tyr residue [220,221], It... 

The electronic spectrum is calculated by using equations 3 and 5. The distortions used in these equations are determined from the pre-resonance Raman intensities by using equations 7 and 9. Both the vibrational frequencies of the normal modes and the displacements of the excited state potential surfaces along these normal modes are obtained from the pre-resonance Raman spectrum. 

The resonance Raman spectrum of K4[Mo2C18] has been reinvestigated using 488.0 and 514.5 nm excitation. An enormous enhancement of the intensity of the Mo—Mo stretching mode relative to the intensity of other fundamentals was observed and an overtone progression in Vj to 5vj identified. From these data the harmonic frequency and anharmonicity constant X, were calculated as 347.1 + 0.5 cm -1... 

Peticolas was the first to measure the UV resonance Raman spectrum and excitation profile (resonance Raman intensity as a function of excitation wavelength) of adenine monophosphate (AMP) [147, 148], The goal of this work, besides demonstrating the utility of UV resonance Raman spectroscopy, was to elucidate the excited electronic states responsible for enhancement of the various Raman vibrations. In this way, a preliminary determination of the excited-state structures and nature of each excited electronic state can be obtained. Although the excited-state structural dynamics could have been determined from this data, that analysis was not performed directly. 

Upon oxidation of T2D, spectral changes104 are also observed for the type 1 copper site (Fig. 41), indicating intersite interaction. The type 1 parallel hyperfine increases to 42.9 x 10-4 cm-1, intensity of the Blue band decreases (Ac614 —300 M-1 cm-1) and the resonance Raman spectrum of the Blue site shows a significant increase in intensity of a 382 cm-1 vibration. These changes demonstrate that the geometry of the type 1 site is affected by oxidation of the type 3 copper in T2D laccase. 

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