Figure 1 shows a 2-dimensional planar arrangement of equally spaced hydrogen atoms, with HH distance = a. a [6] Figure 1 Square lattice. a) Sketch the band structure along (0 0 0)-X(700)-S(72 / 0)-f(0 0 0) for the lattice shown in Figure 1. b) Draw appropriate linear combinations of atomic orbitals at X and S. c) Show how the band structure would change if the H-H distances alternate in a short-long-short pattern along each direction, such that the regular square lattice becomes a collection of isolated squares, as shown in Figure 2. [3] 2a Figure 2 Lattice of isolated squares. Figure 1 shows a 2-dimensional planar arrangement of equally spaced hydrogen atoms, with HH distance = a. a [6] Figure 1 Square lattice. a) Sketch the band structure along (0 0 0)-X(700)-S(72 / 0)-f(0 0 0) for the lattice shown in Figure 1. b) Draw appropriate linear combinations of atomic orbitals at X and S. c) Show how the band structure would change if the H-H distances alternate in a short-long-short pattern along each direction, such that the regular square lattice becomes a collection of isolated squares, as shown in Figure 2. [3] 2a Figure 2 Lattice of isolated squares