A method named for the fragment type of these structures uses energy decomposition analysis and Møller–Plesset perturbation theory for efficient calculation. (-5[1])Repulsion (15[1])in these structures is described by the Klopman–Salem (15[2])equation. (15[2]-5[1])To (15[1])approximate wave functions of these structures, the Hartree–Fock (-5[1])method (15[2]-5[1])uses (15[3]-5[1])the (-5[1])overlap (15[2])integral (15[5]-5[2])between (15[1])Gaussian (15[1])basis functions. (15[3])Depending on their (15[1])behavior (15[1])under inversion, (-5[1])these structures (15[1])are categorized as (*) “gerade” or “ungerade.” The (10[1])“frontier” (10[1])theory (10[1])of these structures (10[4])examines (10[1])their “highest occupied” (10[1])and “lowest (10[2])unoccupied” (10[1])examples. (10[5]-5[1])Electrons (10[1]-5[1])generally occupy the “bonding” (10[1]-5[3])variety of these structures before their “antibonding” (10[1]0[1])variety. (-5[1])Sigma and pi-star are examples of, (10[1])for 10 points, what structures classically (-5[1])formed from the linear combination of atomic orbitals? ■END■ (10[3]0[5])