| Ethylene is the simplest alkene. The carbon--carbon double bond is ubiquitous in the field of chemistry. Ethylene serves as the basis for understanding these molecules. Thus, the assignment of the electronic transitions in ethylene is an important endeavor that many scientists have undertaken, but are yet to decipher theoretically or experimentally.;Synchrotron Radiation in the vacuum ultraviolet region allows for magnetic circular dichroism (MCD) measurements of ethylene and other simple alkenes. Studies of ethylene and propylene revealed that the pi→pi* (Ag→BIu ethylene notation) transition is not the lowest energy transition. The pi→3s(R) (Ag→B3 3u ethylene notation) is the lowest energy transition.;To further this investigation, MCD and absorption measurement were carried out on isobutene. The isobutene spectra clearly showed four electronic transitions in the 156 to 212 nm wavelength region. These four isobutene transitions have been assigned as pi→3s, pi→pi*, pi→3psigma and pi→3px proceeding from lower energy to higher energy. The present results support the assignments in ethylene and propylene. |
