Figure 1.12

Figure 1.12 features a qualitative MO scheme for the pi-MOs of acetylene.

Input file for acetylene:

#p b3lyp/6-31g(d) int=ultrafine scf=tight pop=full gfinput     

C2_01, B3LYP/6-31G(d) int=ultrafine opt=tight C2H2     

0 1       
C,0,0.,0.,0.0475169499
C,0,0.,0.,1.2524830501
H,0,0.,0.,2.3191151942
H,0,0.,0.,-1.0191151942