Fixed points plane filled with

On the other hand, if A = 0, the whole plane is filled with fixed points (No surprise—the system is x = 0.)... 

The relationship between the equilibrium vapor pressures on a concave meniscus and that on a flat surface is given by the Kelvin equation Pr = Pf x exp (-A/r), where r is the radius of curvature of the concave meniscus. In the case of a crevice of constant width, under fixed environmental conditions, r is constant, and hence, there is a critical relative humidity of the atmosphere, at which the crevice is empty and above which the crevice is filled with water. In the case where, instead of a spherical particle on a flat surface, the radius of curvature of the meniscus at the sphere-plane point of contact tends to zero, and hence, the critical relative hnmidity also tends to zero, there does not exist a minimum value below, which, under the particle, there is no water. By increasing the relative humidity of the atmosphere, both the radius of curvature of the meniscus and the amount of water below the particle increase (Figure 12.26). 

Steric factors probably prohibit simultaneous rotation of the olefin and alkyne C2 units which would crowd all four metal-bound carbons into the same plane. Separate rotation of each unsaturated ligand was explored theoretically using the EHMO method. Rotation of the olefin destroys the one-to-one correspondence of metal-ligand tt interactions. Overlap of the filled dxz orbital with olefin n is turned off as the alkene rotates 90°, creating a large calculated barrier for olefin rotation (75 kcal/mol). Alkyne rotation quickly reveals an important point the absence of three-center bonds involving dir orbitals allows the alkyne to effectively define the linear combinations of dxy and dyz which serve as dn donor and dir acceptor orbitals for 7T and ttx, respectively. Thus there should be a small electronic barrier to alkyne rotation (the Huckel calculation with fixed metal... 

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