(1)L(A)-(1)L(B) COUPLING IN THE EXCITED-STATE OF 3-METHYLINDOLE AND ITS POLAR CLUSTERS

The excited state dynamics of 3-methylindole are investigated with the goal of further characterizing the nonadiabatic interaction giving ri se to (1)L(a)-(1)L(b) mixing in its excited singlet state. Both the ba re molecule and its clusters with polar species display evidence of co upling between these two close-lying states. By using a series of succ essively more polar ligands, it is shown that the strength of the inte raction between the (1)L(b) and (1)L(a) states can be ''tuned'', permi tting the observation of progressive changes in excited state behavior . This enables us to relate the present results to previous studies co nducted in this and a number of other laboratories. While each of thes e has concentrated on the measurement of a particular excited state ph enomenon as a signature of (1)L(a) state coupling, the results present ed here are used to show how they can be successfully integrated into a more general picture of (1)L(a)-(1)L(b) state coupling in indoles.