New ab Initio Potential Energy Surfaces for the Renner-Teller Coupled 𝟏^𝟏𝐴^′ and 1^𝟏𝐴^′′ States of CH₂

Figure 5

The stretching potential curves of the five singlet states (1¹𝐴^′, 2¹𝐴^′, 3¹𝐴^′, 1¹𝐴^′′, and 2¹𝐴^′′ state) of CH₂ as functions of the bond length 𝑅_CH2 with the ∠HCH fixed at (a) 180°, (b) 175°, and (c) 160°, respectively; The Renner-Teller terms 𝐿_𝑧^𝑎𝑏, 𝐿^𝑎𝑎_𝑧𝑧, 𝐿^𝑏𝑏_𝑧𝑧, and 𝐿²²_𝑧𝑧 (⟨2¹𝐴^′∣𝐿²_𝑧∣2¹𝐴^′⟩) as functions of the bond length 𝑅_CH2 with ∠HCH fixed at (d) 180°, (e) 175°, and (f) 160°, respectively. 𝑅_CH1 is fixed at 2.09 bohrs, and the zero energy is taken at the CH₂ (1¹𝐴^′) minimum.

(a)

(b)

(c)

(d)

(e)

(f)