Non-collinearity

At the time the experiments were perfomied (1984), this discrepancy between theory and experiment was attributed to quantum mechanical resonances drat led to enhanced reaction probability in the FlF(u = 3) chaimel for high impact parameter collisions. Flowever, since 1984, several new potential energy surfaces using a combination of ab initio calculations and empirical corrections were developed in which the bend potential near the barrier was found to be very flat or even non-collinear [49, M], in contrast to the Muckennan V surface. In 1988, Sato [ ] showed that classical trajectory calculations on a surface with a bent transition-state geometry produced angular distributions in which the FIF(u = 3) product was peaked at 0 = 0°, while the FIF(u = 2) product was predominantly scattered into the backward hemisphere (0 > 90°), thereby qualitatively reproducing the most important features in figure A3.7.5. 

These limitations have recently been eliminated using solid-state sources of femtosecond pulses. Most of the femtosecond dye laser teclmology that was in wide use in the late 1980s [11] has been rendered obsolete by tliree teclmical developments the self-mode-locked Ti-sapphire oscillator [23, 24, 25, 26 and 27], the chirped-pulse, solid-state amplifier (CPA) [28, 29, 30 and 31], and the non-collinearly pumped optical parametric amplifier (OPA) [32, 33 and 34]- Moreover, although a number of investigators still construct home-built systems with narrowly chosen capabilities, it is now possible to obtain versatile, nearly state-of-the-art apparatus of the type described below Ifom commercial sources. Just as home-built NMR spectrometers capable of multidimensional or solid-state spectroscopies were still being home built in the late 1970s and now are almost exclusively based on commercially prepared apparatus, it is reasonable to expect that ultrafast spectroscopy in the next decade will be conducted almost exclusively with apparatus ifom conmiercial sources based around entirely solid-state systems. 

Figure B2.1.2 Modified Michelson interferometer for non-collinear intensity autocorrelation. Symbols used rl, r2, retroreflecting mirror pair mounted on a translation stage bs, beamsplitter x, nonlinear crystal pint, photomultiplier Pibe.

Figure B2.1.3 Output of a self-mode-locked titanium-sapphire oscillator (a) non-collinear intensity autocorrelation signal, obtained with a 100 pm p-barium borate nonlinear crystal (b) intensity spectrum.

Anton, J., Ericke, B. and Schwerdtfeger, P. (2005) Non-collinear and collinear four-component relativistic molecular density functional calculations. Chemical Physics, 311, 97-103. 

The PES is only a function of the shape of the molecule, as described by the internal coordinates (there are ZN — 6 of them for a non-collinear molecule of N atoms). There are many possible choices of internal coordinates, including atom-atom distances (bond lengths), bond angles, dihedral or out-of-plane angles, or some combination of these. However, the PES can be expressed solely in terms of the atom-atom distances (a result that follows from the group theory of functions like the PES which are invariant to rotation).48,49 For N atoms there are NCi = N(N — l)/2 such distances, which are easily calculated from the Cartesian coordinates. Rather than use these atom-atom distances, Rn, we actually use the reciprocal distances, Zn ... 

First, the Dy3 triangle reported by Powell et al., showing SMM behaviour of thermally excited spin states, can be regarded as the archetype of the non-collinear Ising antiferromagnetic arrangement in triangular lattices [28], as seen in several coupled Dy3 (Dy6) complexes [13, 29, 30]. Second, the excellent... 

Disorder and Non-Collinear Magnetism in Permanent-Magnet Materials with ThMn12 Structure. 

Approach to Non-Collinear Magnetism Application to Small Fe Clusters. 

N. Fujima, Eur. Phys.]. D, 16,185 (2001).Non-Collinear Magnetic Moments of Seven-Atom... 

N. Fujima,/. Phys. Soc. Japan, 71, 1529 (2002). Non-Collinear Magnetic Moments of Five-... 

It is easy to determine the environment of Pb in PbZrOs accurately, since PbZrOs is a well ordered compound. But many useful ferroelectric oxides, for instance well-known ferroelectric oxides, Pb(Zr,Ti)03 (PZT), are mixed ion systems in which the crystal sites are occupied by two or more different ions. In such systems it is more difficult to assess the state of Pb off-centering with accuracy using conventional crystallographic analysis, such as the Rietveld refinement. Local Pb displacements are often non-collinear, displaced in different directions from site to site. These local displacements will be observed indirectly only as artificially large thermal factors, and the average displace-... 

The laser system consisted of a home-built Ti sapphire fs laser oscillator and regenerative amplifier (RGA). The pulse duration was 50 fs at 800 nm and 1 kHz repetition rate. The output of the RGA was split into two parts. One part was used as pump pulse. The other part served as a source for the generation of probe pulses with the help of a non-collinear optical parametric amplifier (NOPA, Clark). The sample preparation was explained elsewhere [7]. Briefly, sodium (Alfa Aesar) was used as received and sodium bromide (Alfa Aesar) was dried and re-crystallized under vacuum. The preparation of the samples was carried out in a glovebox under argon atmosphere. Localized electrons were generated by heating the metal-salt mixture to 800 °C, i.e. well above the melting point of the salt. 

The experimental configuration of the pump-probe experiment is similar to Ref. [5]. A home built non-collinear optical parametric amplifier (nc-OPA) was used as a pump, providing Fourier-transform-limited 30 fs pulses, which could be spectrally tuned between 480-560 nm. In all experiments white-light generated in a sapphire crystal using part of the fundamental laser (800 nm), was used as probe light. In the pump-probe experiments the pump was tuned to the S2 0-0 band for carotenoids with n>l 1. In the case of M9, it was not possible to tune the nc-OPA to its 0-0 transition, and hence another nc-OPA tuned to 900 nm was frequency doubled and used for excitation. In addition to conventional transient absorption pump-probe measurements, we introduce pump-deplete-probe spectroscopy, which is sensitive to the function of an absorbing state within the deactivation network. In this technique, we... 

We studied odd, s-wave, triplet superconductivity that may arise in S/F multilayered structures with a non-collinear orientation of magnetizations. It was assumed that the orientation of the magnetization is not affected by the superconductivity (e.g. the energy of the magnetic anisotropy is much larger than the superconducting energy). The analysis was carried out in the dirty limit (Jr -C 1) when the Usadel equation is applicable. 

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