to the behavior of the electronic wave function on application of these operators Consider H2O as an example. In its equilibrium configuration,water belongs to group Car with the symmetry operators EC2(z）o,(Xz）oyz) E C2(z)(xZ)(yz) N 11 1 1 1 1 -1 1 -1 1 -1 B2 -1 -1 1 Consider an operator R that commutes with the molecular Hamiltonian H that does not involve spin;we have RH=HR RHΨ=REΨ HR)=E(RΨ) (8.1) so that R'is an eigenfunction of H with eigenvalue E.We have RΨ=λΨ (8.2) Here must be an eigenfunction of the symmetry operator R.Thus,the electronic states of polyatomic molecules can be classified according to the symmetry of the electronic wave function associated with the molecular point group.For the term classification of H2O,we have such possibilities as A,A2.B,B2,A,etc. As an example,the possible symmetry species of a Dh molecule to be to the behavior of the electronic wave function on application of these operators. Consider H2O as an example. In its equilibrium configuration, water belongs to group C2V with the symmetry operators E C2(z) σv(xz) σv(yz) H1 H2 O y z E C2(z) σv(xz) σv(yz) A1 A2 B1 B2 1 1 1 1 1 1 1 1 -1 -1 -1 1 -1 -1 -1 1 Consider an operator R that commutes with the molecular Hamiltonian H that does not involve spin; we have RH = HR RHΨ = REΨ H(RΨ) = E(RΨ) (8.1) so that RΨ is an eigenfunction of H with eigenvalue E. We have RΨ = λΨ (8.2) Here Ψ must be an eigenfunction of the symmetry operator R. Thus, the electronic states of polyatomic molecules can be classified according to the symmetry of the electronic wave function associated with the molecular point group. For the term classification of H2O, we have such possibilities as 1 A1, 1A2, 1 B1, 1 B2, 3 A1, etc. As an example, the possible symmetry species of a D6h molecule to be