Resonance molecular

Leforestier C and Museth K 1998 Response to Comment on On the direct complex scaling of matrix elements expressed in a discrete variable representation application to molecular resonances J. Chem. Phys. 109 1204... 

A type of molecular resonance scattering can also occur from the formation of short-lived negative ions due to electron capture by molecules on surfrices. While this is frequently observed for molecules in the gas phase, it is not so important for chemisorbed molecules on metal surfaces because of extremely rapid quenching (electron transfer to the substrate) of the negative ion. Observations have been made for this scattering mechanism in several chemisorbed systems and in phys-isorbed layers, with the effects usually observed as smaU deviations of the cross section for inelastic scattering from that predicted from dipole scattering theory. 

There are different paths to achieving surface specificity. One can exploit optical susceptibilities and resonances that are nonzero only at the surface or only for the molecular species of interest adsorbed on the surface. Examples include the use of second-order nonlinear mixing processes such as second harmonic generation7-9 for which the nonlinear susceptibility tensor is nonzero only where inversion symmetry is broken. Spectroscopic techniques with very high selectivity for molecular resonances such as surface-enhanced infrared or Raman spectroscopy10-12 may also be used. 

Basilevsky, M. V. and Ryaboy, V. M. Two approaches to the calculation of molecular resonance states Solution of scattering equations and matrix diagonalization, J.Comp.Chem., 8 (1987), 683-699... 

To conclude, even if there exist several processes that affect the vibrational line shape it seems probable that when most of them have been sorted out and with the good agreement between theory and experiment, the lifetime broadening for a chemisorbed CO molecule is of the order of a few cm, corresponding to a lifetime of a few ps. The main vibrational energy relaxation mechanism is creation of electron-hole pairs caused by the local charge oscillations between the metal and the 2n molecular resonance crossing the Fermi level. 

The rapidly changing trigonometric denominator gives rise to divergences that correspond to the molecular resonances [16,27,28]. We can see that the DOS contains the same divergent term as the transmission, therefore, at least close to the molecular resonances, the transmission seems to be proportional to the scaled DOS, as suggested by the equation defining t (equation (32)). The spectral function (see equation (37)) contains the term Ti + U2, which refers to the contacts... 

To date, all LSPR nanosensor experiments have been performed using non-resonant molecules. Because the effect that molecular resonances have on nanoparticle sensing is unknown, my current studies are aimed at answering this question (Objective 6). Preliminary results indicate that the resonant molecule, Fe(bpy)3 + (bpy = 4,4 -bipyri-dine), dramatically enhances the sensitivity of the LSPR nanosensor when the extinction maximum of the nanoparticles is slightly red-shifted from the molecular resonance. 

Because the effect that molecular resonances have on nanoparticle sensing is unknown, my current studies are aimed at answering this question... 

Preliminary results indicate that the resonant molecule, Feibpyjj " (bpy = 4,4 -bipyridine), dramatically enhances the sensitivity of the LSPR nanosensor when the extinction maximum of the nanoparticles is slightly red-shifted from the molecular resonance. 

Depending on molecular resonances, VOCs with an optical (electronic) absorption at 266 nm absorb a laser photon, while those transparent at 266 nm remain in the ground state. The width of optical absorptions is given by the ground-state population, and broadens with the molecules temperature, which itself depends on the expansion conditions at the inlet system. 

Rotational degrees of freedom can also be included in this scheme that is, we may thus study the effect of rotation on the molecular resonances [23]. 

The Raman scattering signal can also be enhanced if one chooses an excitation wavelength corresponding to an electronic transition of the molecule of interest. This resonance Raman effect can enhance the signal by two to six orders of magnitude [55]. Hence, exploiting both the surface enhancement and the molecular resonance leads to extremely low detection limits (e.g., picomolar and below). 

QMRE RE quantum molecular resonance energy resonance energy... 

The loss intensities are a strong function of the incident electron energy and only average values are reported here. This could be due to molecular resonances or short range "impact" scattering ( , 9, 1(), 96) as discussed by Lehwald and Ibach for the case of acetylene chemisorbed or Ni(lll)... 

B. Simon, The Definition of Molecular Resonance Curves by the Method of Exterior Complex Scaling, Phys. Lett. A71 (1979) 211. 

C.P. Ballance, K.A. Berrington, B.M. McLaughlin, Detection and analysis of interloping molecular resonances, Phys. Rev. A 60 (1999) R4217. 

The most clear demonstration of the predictions of a resonant mechanism of vibrational excitation was provided by Hanh et al. [9]. The authors find a decrease in the conductance associated with the onset of activation of an 0-0 stretch mode, for O2 on Ag(llO). Such reversed behavior follows predictions made by Persson et al. [10] for those systems with narrow molecular resonances around the Fermi level (Ep). The theoretical fundaments of these and related issues will be discussed later in this chapter. 

Ozone is known as a very reactive agent in both water and air. The high reactivity of the ozone molecule is due to its electronic configuration. Ozone can be represented as a hybrid of four molecular resonance structures (see Fig. 2). As can be seen, these structures present negative and positively charged oxygen atoms, which in theory imparts to the ozone molecule the characteristics of an electrophilic, dipolar and, even, nucleophilic agent. 

Absorption, evaporation, polycondensation, UV-initiated polymerization, molecular resonance heating (microwave)... 

One way an optical standard could be provided is by harmonic multiplication of a microwave frequency standard in a synthesis chain. By use of this technique, a laser at 88 THz (3.39 pm) has been made phase coherent with a microwave oscillator. - The best optical frequency standards may be made by locking a local oscillator (laser) to an atomic or molecular resonance line. State-of-the-art accuracies are characterized by measurements on methane stabilized He-Ne lasers in which reproducibilities in the 10— -- range have... 

The observations illustrate that inelastic and thermally activated tunnel channels may apply to metalloproteins and large transition metal complexes. The channels hold perspectives for mapping protein structure, adsorption and electronic function at metallic surfaces. One observation regarding the latter is, for example that the two electrode potentials can be varied in parallel, relative to a common reference electrode potential, at fixed bias potential. This is equivalent to taking the local redox level up or down relative to the Fermi levels (Fig. 5.6a). If both electrode potentials are shifted negatively, and the redox level is empty (oxidized), then the current at first rises. It reaches a maximum, convoluted with the bias potential between the two Fermi levels, and then drops as further potential variation takes the redox level below the Fermi level of the positively biased electrode. The relation between such current-voltage patterns and other three-level processes, such as molecular resonance Raman scattering [76], has been discussed [38]. 

This is the simplest possible case. In real examples there could be two or more molecular resonances within the bandwidth of the cavity. Suppose, in fact, that there are three resonances at frequencies v, 0.7 v and 0.5v, with relative intensities 10, 15 and 7. In this case f(l) would be given by... 

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