Disrotatory Hamiltonian

  

Figure: Disrotatory ring closure leads to bonding $\sigma$ orbital

For disrotatory motions, defining the twist angle $\theta_{1-2}=- \theta_{3-4} \equiv \omega$, we therefore have

$$\left ( \begin{array}{cccc} \alpha&\beta cos \omega & 0 & -\b... ...n^K \omega & 0 & \beta cos \omega & \alpha \end{array}\right )$$