Femtosecond dynamics of cis-trans isomerization in a visual pigment analog. Isorhodopsin

Journal Article · Thu Nov 18 00:00:00 EST 1993 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100148a040· OSTI ID:5651505

Schoenlein, R W ^[1]; Peteanu, L A; Mathies, R A ^[2]; Wang, Q; Shank, C V ^[3]

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1. Lawrence Berkeley Lab., CA (United States)
2. Univ. of California, Berkeley, CA (United States)
3. Lawrence Berkeley Lab., CA (United States) Univ. of California, Berkeley, CA (United States)

The photochemical cis-trans isomerization of the visual pigment analog isorhodopsin is investigated using femtosecond pump-probe techniques. The 9-cis-retinal protonated Schiff base chromophore in isorhodopsin is excited with a 40-fs pump pulse at 500 nm, and the transient changes in absorption are measured from 450 to 570 nm using a 10-fs probe pulse centered at 500 nm and from 570 to 670 nm using a 10-fs probe pulse centered at 620 nm. Immediately following the pump pulse we observed a strong excited-state absorption with a maximum at approximately 530 and a stimulated emission feature extending from 590 to 670 nm. Both of these features persist for 100-150 fs, indicating that the excited-state torsional dynamics of 9-cis isorhodopsin are significantly slower than those of the 11-cis chromophore in rhodopsin. An absorption feature between 525 and 670 nm fully develops in approximately fs, indicating the formation of of photoproduct on this time scale. The isomerization time in isorhodopsin is significantly slower than that of rhodopsin (200 fs). 33 refs., 4 figs.

• DOE Contract Number: AC03-76SF00098
• OSTI ID: 5651505
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 97:46; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
PIGMENTS
ABSORPTION SPECTRA
ISOMERIZATION
PHOTOCHEMISTRY
BIOLOGICAL MATERIALS
LASERS
RHODOPSIN
CHEMICAL REACTIONS
CHEMISTRY
MATERIALS
ORGANIC COMPOUNDS
PROTEINS
SPECTRA
400201* - Chemical & Physicochemical Properties
400500 - Photochemistry
400102 - Chemical & Spectral Procedures