Excitons, in molecular crystals

Craig, D. P., WalmsUy, S. H. Excitons in molecular crystals Theory and applications. London-New York Benjamin 1968. 

D. P. Craig and S. H. Walmsley, Excitons in Molecular Crystals, Benjamin, New York, 1968. 

Craig, D.P. Walmsley, S.H. Excitons in Molecular Crystals Benjamin Amsterdam, 1968. 

Site shift surface excitons in molecular crystals... 

A useful measure for exciton migration is the diffusion length L = (Dto)1/2. Experimental data show that for Frenkel excitons in molecular crystals at room temperature the diffusion coefficient D 10 3 cm2/s and the lifetime of singlet excitons to 10 8s. This gives a typical diffusion length L 10 6cm (for anthracene crystals L 5 10 6cm). 

In Chap. 6, we discussed low-energy optical excitation states, the singlet and triplet excitons and energy transfer. The primary experimental method applied there was optical spectroscopy in the visible, in the near IR and in the UV spectral ranges. In the present chapter, we treat the structure and the dynamics of localised triplet states, of triplet mini-excitons, and of triplet excitons in molecular crystals. The primary experimental method for the investigation of the lowest-energy triplet level Ti is electron-spin resonance (ESR) (Fig. 7.1). 

Craig DP, Walmsley SH (1968) Excitons in molecular crystals. Benjamin, New York... 

---