A linear variation is performed using two orthogonal basis functions ϕ1 and ϕ2 to generate two optimised energies ε1 and ε2 (ε1 ≤ ε2). If the exact ground and first excited state energies are E1 and E2, respectively, the correct statement is
1
Both ε1 and ε2 are lower than E1
2
ε1 lies between E1 and E2
3
ε1 > E2
4
ε2 < E2