Measurement of the dipole moments of excited states and photochemical transients by microwave dielectric absorption

摘要: Time-resolved changes in microwave dielectric absorption have been used to study transients formed by laser flash photolysis. Details of the method and apparatus are given. Applications both measurements dipole moments decay kinetics The lowest triplet states a number aromatic compounds (mostly ketones) measured benzene solution at room temperature. States n..pi..* character generally possess smaller than corresponding ground while ..pi pi..* (for example, fluorenone) larger values state. triplets 4-(dimethylamino)benzaldehyde 4,4'-bis(dimethylamino)benzophenone rather high moment (10.5 8.4 D, respectively) showing their charge-transfer character. state benzil was found zero or near-zero moment, thus confirming that is transstructure. 7 figures, 1 table.