Trigonal contours

Modifications of the passivated Ni surfaces with respect to the nonpassivated one were recorded on two different lateral scales. On a mesoscopic scale of hundreds of nanometers, islands were observed. Their size was found to decrease and their density was found to increase with increasing passivation potential. Their shape varied from trigonal contours with ledges oriented along the main crystallographic directions of the... 

The relation between F2 and FH is similar to that observed between B2 and BH. The FH molecule has a sigma bonding orbital and has three trigon-ally equivalent lone pairs which are almost identical in character and shape to the corresponding lone pairs of F2. These contracted lone pairs are less sensitive to the other atom than those on B. We also find nearly complete transferability between the inner shells. Here again the outermost contour is 0.025 Bohr 3/2 and the increment of those contours which are shown is 0.2 Bohr 3/2. 

Figure 10 Projection of the potential energy surface for [M(unidentate A)(unidentate B)4] on to the 4>t> 4>E plane (in degrees). The five faint contour lines are for successive 0.01 increments in X above the minima, and the five heavy contour lines are for successive 0.1 increments above the minima, at T0 and T2. R = 0.8. The positions of the trigonal bipyramids (T) and square pyramid (S) are shown...

Fig. 8. Contour map of a trigonal bonding orbital in N2. Courtesy of Professor Klaus Ruedenberg...

Figure 10 Copper coordination geometries in 2,3QD. (a) Experimental map contoured at the 1.0 r (blue) and 2.5 r (green, only for Glu73 and the solvent molecule) levels, (b) Major distorted tetrahedral coordination, (c) Minor trigonal hipyramidal coordination with a strong square pyramidal component. (Ref. 45. Reproduced by permission of Blackwell)...

Fig. 5. The icosahedral T x h problem contour plot of the icosahedral warping term (see Eq. 19) on the unit sphere in function space. The coordinate frame refers to the three cartesian components of the T state. is the vibronic coupling constant. Positive, zero, and negative values of "ITj are represented respectively by full lines, ts, and dashed lines. For E < 0, the function has minima in pentagonal epikemels (Dsd) and maxima in trigonal epikemels (D3d). For > 0, minima and maxima are interchanged. In either case the transition states, TS, coincide with epikernel points...

Fig. 6. The cubic T x (e + 12) problem contour plots of the octahedral warping terms and (see Eq. 20). E4 and E are the relevant vibronic coupling constants. Positive, zero, and negative values are represented respectively by full lines, dots, and dashed lines. The upper part of the figure represents the fourth rank warping term 1 4. This term yields tetragonal (E4 < 0) or trigonal (E4 > 0) minima. In either case the transition states, TS, coincide with the D, (C, epikemels (Cf. Table 3). The lower part displays the sixth rank warping term Iff. This term clearly has a more complex structure. For < 0, it yields minima at the t)2h epikemel points for Es > 0, both Dm and D41, are stabilized, D21, now being on a hill top. In either case the transition states, TS, coincide with the lower ranking epikemels. (In tetrahedral symmetry the D41, I 3d) D2h nd...

Figure 12. Total energy (per formula unit) of NijAl as a function of volume and c/a ratio, characterizing the trigonal deformation, calculated within the GGA. The energy is measured relative to the energy of the equilibrium FM LI2 state (the minimum at c/a = 1). Only states with the minimum energy are shown. The contour interval is 20 mRy. Thick line shows the NM/FM phase boundary. The ground-state minimum at c/a = 1 and the saddle point at c/a - 0.5 (outside the figure area) are dictated by symmetry.

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