Dependence of radiationless relaxation in acridine on solvent using picosecond spectroscopy

We have studied by means of picosecond spectroscopy the solvent dependence of internal conversion, intersystem crossing, and quantum yield of intersystem crossing of acridine in hexane, acetonitrile, isopropanol, and ethanol by following the growth rate of the Tn ←T1 transient absorption. Solvent dependence of the measured lifetime of the lowest excited singlet and the quantum yield of intersystem crossing on solvent strongly indicates that the 1nπ*–1ππ* vibronic interaction, through a distortion of the lowest excited singlet state, is responsible for the unusual solvent dependent fluorescence behavior of this molecule.

[1]  Mostafa A. El-Sayed,et al.  Spin—Orbit Coupling and the Radiationless Processes in Nitrogen Heterocyclics , 1963 .

[2]  T. Netzel,et al.  Picosecond kinetics of tetracene dianions , 1974 .

[3]  R. Becker.  Theory and interpretation of fluorescence and phosphorescence , 1969 .

[4]  E. J. Bowen,et al.  HYDROGEN BONDING OF EXCITED STATES , 1962 .

[5]  L. Goodman,et al.  Calculation of n→II Transition Energies in N‐Heterocyclic Molecules by a One‐Electron Approximation , 1959 .

[6]  Y. Hirata,et al.  Build-up of T—T absorption of acridine following singlet excitation with a picosecond pulse , 1976 .

[7]  A. Kellmann.  Intersystem crossing and internal conversion quantum yields of acridine in polar and nonpolar solvents , 1977 .

[8]  E. Land.  Extinction coefficients of triplet-triplet transitions , 1968, Proceedings of the Royal Society of London. Series A. Mathematical and Physical Sciences.

[9]  V. Zanker.  I. Die Tieftemperaturspektren einiger homologer sechsgliedriger N-Heterocyclen und ihre Entwicklung zu den Spektren der Acridinfarbstoffe. , 1954 .

[10]  E. C. Lim,et al.  Electronic relaxation of acridine as studied by picosecond spectroscopy , 1977 .

[11]  A. Kellmann,et al.  Photoreactive State of Acridine in Solution , 1965 .

[12]  E. C. Lim,et al.  Quantitative Study of Luminescence in Aromatic and Heteroaromatic Molecules , 1972 .

[13]  Jerome W. Sidman.  Electronic Transitions Due To Nonbonding Electrons Carbonyl, Aza-Aromatic, And Other Compounds , 1958 .