Phase diagrams diatomic molecules

FIGURE 9.13 Le Chatelier s principle predicts that, when a reaction at equilibrium is compressed, the number of molecules in the gas phase will tend to decrease. This diagram illustrates the effect of compression and expansion on the dissociation equilibrium ot a diatomic molecule. Note the increase in the relative concentration of diatomic molecules as the system is compressed and the decrease when the system expands. 

Diatomic hydrogen, H2, also exhibits a rich and remarkable complex soUd phase diagram. At low temperatures, when a H2-based solid is formed, electrons are confined in the H2 molecules and the soUd is thus a large-gap insulator. E. Wigner and H. B. Huntington predicted in 1935 the possibiUty of preparing... 

Figure 6.7. Potential energy diagram for the approach of a diatomic molecule from the gas phase to the surface along with the corresponding orbital diagrams.

Fig. 6.3. (a) A one-dimensional lattice of diatomic molecules, (b) The formation of the bonding and antibonding molecular orbitals from i -type atomic orbitals. The lower part of the figure shows the four critical forms of the combination (1-4) the formation of the chemical bond lifts the degeneracy of the out-of-phase combinations of cr and ff and a gap opens between the so-called valence (filled) and conduction (vacant) bands. The band diagram is almost equivalent to that of Fig. 6.2, left, folded back at half its width (the periodicity is doubled) except for the gap alk = a /2 (actually, one half of the former a /2). 

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