Transition start

This last transition moment integral, if plugged into equation (B 1.1.2). will give the integrated intensity of a vibronic band, i.e. of a transition starting from vibrational state a of electronic state 1 and ending on vibrational level b of electronic state u. 

The second-order nonlinear optical processes of SHG and SFG are described correspondingly by second-order perturbation theory. In this case, two photons at the drivmg frequency or frequencies are destroyed and a photon at the SH or SF is created. This is accomplished tlnough a succession of tlnee real or virtual transitions, as shown in figure Bl.5.4. These transitions start from an occupied initial energy eigenstate g), pass tlnough intennediate states n ) and n) and return to the initial state g). A fiill calculation of the second-order response for the case of SFG yields [37]... 

The destruction term is defined as the sum of all irreducible transitions starting from any initial state pk p 0) with k 0 and ending with the zero wave number state (the vacuum ) ... 

Phosphorescence excitation spectroscopy also allows us to observe the transitions starting at 389 nm to the second triplet state, which is of (n,n ) nature. Direct spin-orbit coupling (mechanism I) to a Sn n,n ) state introduces strong in-plane, long-axis polarization. Indeed, in-plane polarization is preferred over out-of-plane polarization by 3 1, and long-axis polarization is about four times stronger than the short-axis contribution. 

Using this technique, Novak and Windsor were able to measure the absorption spectra of several excited aromatic molecules. The observed transitions started from the first excited singlet state S to higher lying states S The authors could also observe... 

In a pulse NMR experiment, the z magnetization is flipped into the xy plane, and the individual transitions start to process. During the detection,... 

Formation of a condensed 2D hep Pbajs phase from an expanded 2D Pbads phase via first-order phase transition starting at steps... 

The fi transition starting at 1 Hz around - 120 °C and extending to higher and higher temperatures when increasing the crosslink density, comes from motions of the hydroxypropyl ether sequence. Isolated and insensitive to crosslink density or amount of antiplasticiser in the low-temperature part of the fi transition, these motions become more and more cooperative as temperature increases. 

Fig. 3 Signature splitting indicated by the differences in Ey (I+I-l) values for transitions starting from the a=-l levels (open squares) and the a= levels (open circles). The corresponding full points give the B(Ml,r T-l)/B(E2,...

The dominant decay branches which result from Is ionization in neon are shown in Fig. 2.5. The fluorescence decay concerns the dipole transitions 2p - Is, shown in the upper row. In the X-ray nomenclature they are called K-L2 3 transitions where the dash is used to separate the initial and final hole-states. These transitions are also called Ka, 2 transitions (see Fig. 2.2). As can be seen in the experimental fluorescence spectrum shown in Fig. 2.6, in addition to these K-L2 3 main transitions there are other lines called satellites. These satellites result from KL-L2 and even KL2-L3 transitions where the dash again separates initial and final hole-states, e.g., KL-L2 radiative transitions start with two holes, one in the K-shell, and one in the L-shell, and they end with two holes in the L-shell. 

A similar effect as in the case of CsSmp has been observed by Yoo et al. (1991). In their study on the Sm2+ ions in SrF2 they could demonstrate an electronic crossover connected with a phase transition starting at pressures around 4.5 GPa. At this pressure, the f-d configuration shifted below the 5Dq multiplet. 

For the explicit form of the integral < f Qp i > it is assumed that Qp is a normal mode and the vibration p therefore harmonic, and that f <- i is a fundamental transition. If the transition starts from a level other than the level np = 0, where np is the vibrational quantum number, then the right-hand side of Equation (2.120) must be multiplied by s/n +T for an upward and frTp for a downward transition. The form (2.120) for Tf< t further implies the electrical harmonic approximation by assuming that derivatives of Te higher than the first one vanish. 

The change in the population distribution ATj(t) of the i th level due to the pump excitation is ANi(t). Let us assume for simplicity that a single AN(t) population is induced. There is a new absorption associated with this population, given by Aa(ui) = a(uj)AN(t). [Usually many excited states i are involved, and more than one transition starts from each state with rates proportional to aij(u>)ANi, so that the real equation is a sum over i and j] AN(t) depends on the material and is represented by the impulsive response function A(t) (i.e., the response to a delta-like pulse). Given the finite duration of the pulse, shorter but not negligible compared with A(t), the real change in a is described by a convolution ... 

In the adiabatic Bom-Oppenheimer approximation, the eigenstates of the unperturbed molecule, i. e. i >, / >, and r >, may be expressed as products of electronic, vibrational, and rotational states. In the following we restrict our discussion to the vibrational resonance Raman effect and hence, assuming that the molecule is initially in the vibrational state u, > and that the Raman transition starts and terminates in the ground electronic state g >, we may write... 

Other specimens showed, in the beginning, near the insert film the saw-tooth pattern with a gradual transition to an increasing area with a smooth surface (Fig. 3). At least three specimens with symmetric and two with non-symmetric lay-up showed this transition initiating on the specimen edge near the starter film. In some specimens, this transition started at a later stage, usually inside the fracture surface, not at the edge. 

After a first sweep towards the positive which is not shown in the diagram and which is dominated by the dissolution of the airfoimed oxide layer, a sweep in the positive direction starts at the negative potential end of the cathodic part of the curve. In the first part, from A to the corrosion potential B where the curve becomes anodic, Hj evolution is the most important process. In this region both samples are very similar. The corrosion potential at B is nearly the same for unimplanted, with Cr implanted and with Ar bombarded iron. From B to C the anodic dissolution of the metal takes place and at C the active to passive transition starts. Here one observes the most significant difference between the two samples. The critical current density for passivation of implanted iron is more than one order of... 

The result shown in Fig. 6.8 that the two species of crystallites respond to the mechanical field in sequence - first the homo-PBT crystallites and later those arising from PEE, means that the homo-PBT crystals are probably dispersed within PEE in such way that they experience the mechanical field from the very beginning of loading. Moreover, one can assume that in the blend some internal stress and/or strain pre-exists since the strain-induced polymorphic transition starts even at lower... 

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