Quasi-line phosphorescence spectra of the copper complex of meso-tetrapropylporphin at liquid helium temperature

Quasi-line spectra of the T-4(1)-->S-2(0) phosphorescence of Cu meso-tetrak is(n-propyl)porphin in n-octane at 4.2 K under wide-band and selective exci tation have been obtained and analysed. A non-typically large distance betw een the edge components of the origin 'multiplet' (175 cm(-1)) indicating t he sensitivity of the energy of the 0-0 transition of molecular impurity ce ntres to the surroundings has been noted, which can lead to a significant i nhomogeneous broadening in amorphous media. Two vibrations with frequencies of about 220 cm(-1) are predominantly active in the phosphorescence spectr um. Unlike Cu porphin, the intensity of the corresponding quasi-lines is lo wer than the intensity of the 0-0 transition. From the broadening of the Q( 0-0) band in the phosphorescence excitation spectrum at selective recording of the 0-0 quasi-line the lifetime of the level S-2(1) (Q) has been determ ined as 35 fs. Copyright (C) 2000 John Wiley & Sons, Ltd.