sudden polarization
The occurrence of a large intramolecular charge separation in the singlet excited state of polyenes and their derivatives twisted about a double bond. Non-symmetrical substitution or geometrical distortion is effective in polarizing the system. An example is the stabilization of the zwitterionic structure of 90° twisted ethene with one methylene group pyramidalized:
PAC, 1999, 71, 1919. 'Glossary of terms used in theoretical organic chemistry' on page 1964 (