Calculation of Ground and Excited State Polarizabilities of Unsubstituted and Donor/ Acceptor Polyenes: A Comparison of the Finite-Field and Sum-Over-States Methods§

In this manuscript, a relatively simple and inexpensive INDO/SCI finite-field (FF) method for calculating polarizabilities (R) is demonstrated to give good agreement with results obtained by both the INDO/MRD/ SDCI sum-over-states routine and published results using the RPA method. The FF method is as effective as the other techniques in predicting both ground and excited state R’s in all substituted and unsubstituted polyenes studied. We observe the correlation described by Marder and co-workers between bond-order-alternation (BOA) and dipolar properties, such as the change in R between the ground and excited states (∆R). In addition, qualitative, but not quantitative, agreement is seen between the calculated ∆R’s of polar polyenes and those measured by Stark-effect spectroscopy.