SYNTHESIS AND 3RD-ORDER NONLINEAR-OPTICAL PROPERTIES OF LINEAR P-ACENEQUINONES

The synthesis of 1,4-tetracenequinone (Q[3,0]) has been described, and the nonlinear optical properties of this quinone together with p-benz oquinone (Q[0,0]), 9,10-anthraquinone (Q[1,1]) and 6, 13-pentacenequin one (Q[2,2]) have been investigated with 532 nm and 8 ns pulses. For t he quinones of Q[0,0], Q[1,1] and Q[2,2], we applied the nonlinear tra nsmittance and the z-scan techniques to determine their two-photon abs orption (TPA) coefficient beta and the third-order nonlinear refractiv e index n(2)(eff). The results show that their beta values increased w ith increasing aromatic rings of quinone, and the magnitudes of n(2)(e ff) and chi(eff)((3)) are all approximately the order of 10(-10) e.s.u . with negative sign. The feasible vertical transition states among th eir low-lying electronic energy levels have been predicted. For Q[3,0] , its excited-state absorption cross section sigma(ex)(T) and the exci ted-state refractive-index cross section a, have been measured with z- scan methods. The magnitudes of sigma(r) and n(2)(eff) are comparable with those of well-known highly conjugated planar molecules of tetrabe nzoporphyrin and metallophthalocyanines. (C) 1998 Elsevier Science S.A .