Unrelaxed structure

Figure 20 Unrelaxed structure of the TiO2(110) surface with bridging oxygen rows. (From Ref. 41.)...

Figure 40 A 12-layer slab model of the Al-terminated (0001) surface of a-Al203. Lateral view of the unrelaxed structure (left) and the relaxed structure (right).

Gain in energy (in kj/mol) with respect to the unrelaxed structure. 

Table 26 Convergence of the MgO [Li]° Defect Formation Energy (in kJ/mol) in the 844 Supercell with Respect to Structural Relaxation (in A) Allowed up to the Fourth Nearest Neighbors of the Defect in the Otherwise Unrelaxed Structure (changes in the geometry around the defect are also reported)...

The free energy of P+Bm" can be calculated from that of P+Bl if we take the value of a for the process Bl"Bm BlBm" to be zero, which should be an acceptable approximation. The calculated electrostatic stabilization of Bm" in the reaction center turns out to be much less favorable than that of Bl". In the unrelaxed structure, P+Bm" is calculated to lie 6.1 kcal/mol above P+Bl", or about 4 kcal/mol above P. ... 

Figure 18. The unrelaxed structure of the (100) surface of galena. Both Pb and S are equally arranged in a face-centered cubic array across the siuface. Perpendicular to the surface plane, the surface can be seen to be built up from stacks of charge neutral atomic planes. The sitrface is type 1 and electrostatically stable (see Fig. 3).

The defect-formation energy of the F+ center is smaller than that of the F center in both the relaxed and the unrelaxed structures using Pe = 0 for the chemical potential of the electrons. This agrees qualitatively with the results of [712] when compared to... 

Surface crystallography started in the late 1960s, with the simplest possible structures being solved by LEED [14]. Such structures were the clean Ni (111), Cu(l 11) and Al(l 11) surfaces, which are unreconstructed and essentially unrelaxed, i.e. very close to the ideal temrination of the bulk shown in figure B 1.211 a) typically, only one unknown structural parameter was fitted to experiment, namely the spacing between the two outennost atomic layers. 

The picosecond TR experiments described above for BR reveal that a hot unrelaxed J intermediate with a highly twisted structure forms and then vibrationally cools and conformationally relaxes within 3ps to form the K intermediate. Subsequently, an isomerization induced protein conformational change takes place during 20-100 ps to produce the KL inermediate. ... 

Figure 1,2 Atomic arrangement on various clean metal surfaces. In each of the sketches (a) to (h) the upper and lower diagrams represent top and side views, respectively. Atoms drawn with dashed lines lie behind the plane of those drawn with thick lines, Atoms in unrelaxed positions (i.e. in the positions they occupy in the bulk) are shown as dotted lines. From G.A. Somorjai, Chemistry in Two Dimensions, Cornell University Press, London, 1981, p. 133, For the Miller index convention in hexagonal close-packed structures, see also G.A. Somorjai loc. cit, Used by permission of Cornell University Press,...

Figure 4.1. /3-(BEDT-TTF)2PF6 Pnna, a = 1.496 nm, b = 3.264 nm, c = 0.666 nm). Structural models for the (a) unrelaxed and (b) relaxed ac-surface layer. C and S atoms are represented by black and medium grey balls, respectively. Adapted from Ishida et al, 2001.

The electron density distribution of a known surface structure can be calculated from first-principles. Thus, the He diffraction data can be compared with theoretical results, in particular, to verify different structural models. Hamann (1981) performed first-principles calculations of the charge-density distributions of the GaAs(llO) surface, for both relaxed and unrelaxed configurations. The He diffraction data are in excellent agreement with the calculated charge-density distributions of the relaxed GaAs(llO) surface, and are clearly distinguished from the unrelaxed ones (Hamann, 1981). 

In some cases, data obtained through the Forster cycle show similar inconsistencies, depending on whether absorption or emission is used. It may well be that either the equilibrium structure in the excited state is very different from the unrelaxed Franck-Condon one, or that 0-0 frequencies are too poorly estimated. It seems, therefore, that the most reliable results are those generated by method (3). This method has been applied to the study of carbazole (3) acidity in its S, state (85MI5). 

The ultrafast photoreactions in PNS of these proteins take place immediately after conversion from the FC state to vibrationally unrelaxed or only partially relaxed FI state [1-3]. For PYP [1] and Rh [3], the primary process is twisting of the chromophore, which causes the ultrafast fluorescence quenching, in the course of the isomerization, while the primary process for FP [2] is the ultrafast electron transfer leading to the fluorescence quenching reaction in PNS. Thus, in spite of the different molecular structures of PYP, Rh and FP chromophores and different kind of photoinduced reactions, these photoresponsive proteins show ultrafast and highly efficient photoreactions from FI state of similar nature (vibrationally unrelaxed or only partially relaxed), suggesting the supremely important role of the PNS controlling the reactions. 

Table 2 Equilibrium bond lengths (in a.u.) and total binding energies (in eV) of the Oh find C3v isomers of the Na Pb cluster. Distances r, r2) r3, r4 are indicated in Fig. 11. The asterisk in the C3v structure indicates our unrelaxed calculation with the bond lengths taken from Jinlong [42].

For species adsorbed on (2116) faces, the experimental frequencies are closer to those calculated for relaxed structures than to those obtained for unrelaxed models. This result is expected because the backrelaxation induced by the reversibly adsorbed CO on this highly coordinatively unsaturated and strongly relaxed surface is quite modest. 

The best evidence so far for the glassy nature of HDA was provided (1) by measurements of the dielectric relaxation time under pressure at 140 K [206, 251], (2) by the direct vitrification of a pressurized liquid water emulsion to HDA [252], and (3) by a high-pressure study of the glass >liquid transition using differential thermal analysis (DTA) [253], We note here that these studies probe structurally relaxed HDA (eHDA) rather than unrelaxed HDA. It is possible that structurally relaxed HDA behaves glass like, whereas structurally uHDA shows a distinct behavior. Thus, more studies are needed in the future, which directly compare structurally relaxed and unrelaxed HDA. 

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