Ground vibrational states

Knopp G, Pinkas I and Prior Y 2000 Two-dimensional time-delayed coherent anti-Stokes Raman spectroscopy and wavepacket dynamics of high ground-state vibrations J. Raman Spectrosc. 31 51... 

Section 6.13.2 and illustrated in Figure 6.5. The possible inaccuracies of the method were made clear and it was stressed that these are reduced by obtaining term values near to the dissociation limit. Whether this can be done depends very much on the relative dispositions of the various potential curves in a particular molecule and whether electronic transitions between them are allowed. How many ground state vibrational term values can be obtained from an emission spectrum is determined by the Franck-Condon principle. If r c r" then progressions in emission are very short and few term values result but if r is very different from r", as in the A U — system of carbon monoxide discussed in Section 7.2.5.4, long progressions are observed in emission and a more accurate value of Dq can be obtained. 

As described above, the ground state vibrational wavefunction is totally symmetric for most common molecules. Therefore, the product, -(1)0 must at least contain a totally symmetric component. The direct product of two irreducible representations contains the totally symmetric representation only if the two irreducible representations are identical. Therefore, transitions can occur from a symmetrical initial state only to those states that have the same symmetry properties as the transition operator, 0. 

The factor Dg can either be determined from the dissociation energy and the ground state vibration energy or from thermodynamic data. The heat of formation of H atoms from H2 molecules can be found in the literature, but some care should be exercised in considering the total energy content of H atoms and H2 molecules under standard conditions. 

The equilibrium bond length (R,.) and ground state vibrational frequencies (( ,) computed at the DF and RASCI levels, are compared with experiment and with other calculations in Table IV. It is evident from Table IV that the RASCI method offers a more accurate estimate of R(, than the DF approximation, while the later method yields a more accurate estimate of the vibrational frequency ooe. However, the minuscule error in ( , (at the DF level) is perhaps fortuitous given the larger error in Rf of 2.8%. 

Fig. 12 Nuclear motion of the ground-state vibration at 243 cm-1 (calculated,...

Vijay, A., and D. N. Sathyanarayana. 1992. Theoretical Study of the Ground-State Vibrations of Nonionized Glycine. J. Phys. Chem. 96, 10735-10739. 

Fig. 1.8. Ground state vibrations resulting from Lochfrass and bond-softening showing different phases of the motion. The pulse duration is 25 fs. The intensity is 2.5 1014Wcm-2 for Lochfrass and 3.4 1013Wcm 2 for bondsoftening. These were chosen to make the amplitude of the motion the same for the two processes. The vibrational phase does not depend on intensity. The wavelength for the bond-softening calculation is 400 nm...

Flash photolysis experiments95, 97 have revealed the presence of S2(3E ) iQ its ground vibrational state. There is good reason to believe, however, that the product of reaction between S(1D2) and COS is S2(XA9) or S2(XS4) which is collisionally deactivated slowly to the ground state. Vibrational relaxation in the 3E state is very rapid. S2(3 ) disappears in a second-order reaction, presumably... 

The potential energy curves of the species AB, AB+, and AB- are used in figure 4.1 to summarize the definitions of the adiabatic ionization energy and electron affinity of AB. Note that the arrows start and end at vibrational ground states (vibrational quantum number v = 0). 

IDSRS) and the complementary resonance ion-dip IR spectroscopy (RID1RS) are useful mass selective techniques for the probing of cluster ground state vibrations. 

R. Bigwood, B. Milam, and M. Gruebele. The ground state vibrational structure of SCClj observation of backbone IVR. Chem. Phys. Lett., 287(4) 333-341(1998). 

Figure 3. Potential energy (solid line), kinetic energy (dashed line), and total energy (dot-dashed line), for an anharmonic (top panel) and harmonic (bottom panel) oscillator with the same ground state vibrational frequency. The parameters are the same as in Figure I.

The mechanism of control with multipulse excitation is likely due to dynamics of the carotenoid donor. The presumably incoherent EET process [1] would not support the observed dependence on the carrier phase via the parameter c. Furthermore, the control effect does not suffer from annihilation at higher excitation intensities [2], as would be characteristic for the delocalised excitons in the B850 ring [1], However, it is well known that femtosecond pulses populate higher ground state vibrational levels by impulsive Raman scattering (IRS) [4], and that the periodic phase modulation (Eq. 1) makes IRS selective for specific vibrations... 

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