Energy level diagram Raman scattering

Figure 3.1. Simple schematic diagram of resonance Raman scattering in a harmonic system. The initial state i> is excited by the incident photon of energy El that is resonant with the set of energy levels v>. The scattering of the photon with energy Eg takes the system from i> to f>.

Figure 1. Energy level diagram for Raman scattering, (a) Stokes Raman scattering, and (b) anti-Stokes Raman scattering.

Fig. 2 Jablonski energy level diagram illustrating possible transitions, where solid lines represent absorption processes and dotted lines represent scattering processes. Key A, IR absorption B, near-IR absorption of an overtone C, Rayleigh scattering D, Stokes Raman transition and E, anti-Stokes Raman transition. S0 is the singlet ground state, S, the lowest singlet excited state, and v represents vibrational energy levels within each electronic state.

Figure 7.1 Energy level diagram Illustrating changes that occur in IR, normal Raman, resonance Raman, and fluorescence. Notation on the figure stands for Rayleigh scattering (R), Stokes Raman scattering (S), and anti-Stokes Raman scattering (A). Reprinted from Ferraro et al. (2003) [4] with permission from Elsevier.

Energy level diagram for Rayleigh (left) and Raman (right) scattering. 

Fig. 8.12 The Raman effect. Monochromatic light of frequency vQ is scattered by a sample, either without losing energy (Rayleigh band) or inelastically, in which a vibration is excited (Stokes band), or a vibra-tionally excited mode in the sample is de-excited (anti-Stokes band). The spectrum is that of the light scattered by the sample. The energy level diagrams illustrate that the scattering process occurs via highly unstable states of high energy.

Figure 3-43 Schematic representation of the photoacoustic Raman scattering (PARS) process, (a) A simple energy level diagram illustrating the Raman interaction that occurs in the PARS process, (b) Basic elements of the PARS experimental arrangement. The pump beam is attenuated and the Stokes beam is amplified by the stimulated Raman process that takes place where the beams overlap in the gas sample cell. For each Stokes photon created by the Raman process, one molecule is transferred from the lower state to the upper state of the transition. Collisional relaxation of these excited molecules produces a pressure change that is detected by a microphone. (Reproduced with permission from Ref. 107.)...

Coherent Anti-Stokes Raman Scattering (CARS). In addition to the nonpara-metric SRS process to generate Stokes-shifted beams that propagate collinearly with the vq pump radiation, a second parametric process can occur that generates noncollinear beams at frequencies Vsi = vq + I yand vsi = vq - Vj. The energy level diagram for... 

Figure 4.3. The energy level diagram showing the basic transitions involved in the spontaneons Raman scattering.

Figure 1.1. Energy level diagrams for spontaneous Raman scattering.

Figure 10.2 Energy level diagram for Raman scattering. A photon is incident at frequency u and a photon is scattered at frequency cj the energy difference h uj - uj ) matches a molecular level separation E — E. The dashed line corresponds to a virtual state, which need not coincide with any eigenstate of the molecule (Section 10.1).

Figure 11.2 Energy level diagram for the process represented by graph (b) in Fig. 11.1. The process is sum-frequency generation when states k and /n> are the same, and hyper- k> Raman scattering when they are different.

An energy-level diagram is given in Fig. 1, which illustrates IR absorption and Raman scattering. In both cases the initial state is the zeroth vibrational level of the ground... 

Figure 1 Energy-level diagram for infrared absorption and stokes Raman Scattering for a vibrational transition from 0 to gl. The scattering photon energy, is shifted from the incident laser radiation energy by the infrared vibrational energy, gained by the molecule.

Figure 1. (a) Light at frequency coj scattered by molecular vibrations generates a Raman shifted signal at 0,. (b) Energy level diagram illustrating the Raman process, (c) Raman peaks are expressed... 

In addition to CARS, other closely related but less commonly used nonlinear Raman techniques have been developed. The energy level diagram for coherent Stokes Raman spectroscopy (CSRS) is shown in Figure 1. Unlike CARS, CSRS is nonparametric the final state is not the same as the initial state. Therefore, CSRS spectra may exhibit extra peaks due to coherence dephasing. Furthermore, the CSRS output beam is generated to the Stokes (lower frequency) side of 0)3. CSRS is therefore more susceptible to spectral interference from fluorescence and Rayleigh scattering of the input beams. 

Fig. 1.3 Pulse sequence top) and energy level diagram bottom) for third-order left) and fifth-order right) Raman spectroscopy. The nonresonant third-order spectroscopy consists of a pair of time-coincident pump pulses (ki, k2) followed by a probe pulse (ks) after a time delay t. The fifth-order nonresonant spectroscopy consists of two pump pulse pairs (ki, k2, and ks, k4) separated by a time delay T2, followed by a probe pulse (ks) after a second time delay T4. In both cases a signal field (ks) is generated by the scattering of the probe off the pump-induced grating in the sample...

---