Transient visible absorption in infrared saturable absorbing dyes

Autor:	G. L. Olson, G. E. Busch
Rok vydání:	1978
Předmět:	Wavelength Infrared Atomic electron transition Chemistry Picosecond General Physics and Astronomy Saturable absorption Physical and Theoretical Chemistry Atomic physics Molar absorptivity Photochemistry Ground state Excitation
Zdroj:	The Journal of Chemical Physics. 68:573-578
ISSN:	1089-7690 0021-9606
DOI:	10.1063/1.435767
Popis:	An optically generated transient absorbing state in the polymethine pyrylium dyes EK 9860 and 9740 is described. The broadband absorption is produced when solutions of the dyes are irradiated by a 1060 nm picosecond duration pulse. The absorbing state spans the wavelength range from ∼520 to ≳800 nm and is characterized by a molar extinction coefficient of ∼1×104 and by a decay time as short as 13.4 psec (in 9860). The latter result and the 7 psec value previously reported for the recovery of ground state absorption at 1060 nm following excitation at the same wavelength are accommodated by a three level relaxation mechanism. This approach treats the visible absorption as arising from electronic transitions both from the first excited singlet state and from a transient intermediate level. Lack of structure in the transient visible absorption indicates that the transition populates high density bound state manifolds or continuum states.
Databáze:	OpenAIRE
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