Formulation Rhombi Chain along the 11 Direction

The 3B premise provides an alternative view on the reconstruction suggesting that O, N, and C tend to find their own environment to form the tetrahedron with bond and nonbond creation. Tetrahedron bond formation drives the radial and the subsequent clock reconstruction on the O-Rh(OOl) surface. Meanwhile, the 0 transits into an 0 with sp-orbital hybridization. The ip-orbital hybridization also holds for the C and N when they react with the Ni(OOl) surface. The electrostatic 

This -induced phase transits into the Rh(001) 2(l x 1)R45°-160 phase (see the corresponding deformed unit cell in Fig. 3.24b)  

The p4g STM images induced by C, N and 0 exhibit the same rhombi chain despite the rotation angle. Linking the Ni ions labeled 1 in N-Ni(OOl) surface (see Fig. 3.25b) matches ideally the orientations of the STM depressions. This configuration verifies that the radius of an Ni ion is much smaller than that of an Ni. Therefore, using a proper bonding scheme, one is able to identify individual atomic valence and the bond relaxation dynamics from the STM images. 

As the 0 has already bonded to one Rh atom underneath, the tetrahedron defines one Rh (labeled 1) and two lone-pair-induced Rh dipoles (labeled 2) of the four nearest surface neighbors. The RhsO Rh40 transition gives rise to the overall p4g reconstruction. As can be seen from the primary unit cell containing the adsorbate (Fig. 3.24b), three of the four surface neighbors are labeled with 1,2, and 2, respectively. Because the surface atomic ratio 0 Rh =1 2 and each oxygen bonds to one atom at surface and needs two atoms to be polarized, half of the overall surface atoms are thus defined as Rh and another half as Rh P. The Rh P contributes to the H-like bond. 

One can find that atoms labeled 1 change their positions in a clockwise fashion if one counts the O-occupied hollows along the (11) direction (gray thick lines). The adsorbate dislocates eccentrically in the (11) direction in a periodic way. From this point of view, it would be essential and complete to consider a c(4 2 X 4.y2)R45°-160 complex unit cell in practice due to the periodicity of the off-centered adsorbate positions. Strikingly, the rhombi hollows without adsorbates form chains along the (11) direction. The above argument is also applicable to the (N , C )-Ni(001) surfaces. 

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