Baker, Lewis A., Clark, Sarah L., Habershon, Scott and Stavros, Vasilios G. (2017) Ultrafast transient absorption spectroscopy of the sunscreen constituent ethylhexyl triazone. The Journal of Physical Chemistry Letters, 8 (10). pp. 2113-2118. doi:10.1021/acs.jpclett.7b00633 ISSN 1948-7185.

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Abstract

The ultrafast photoprotection mechanisms in operation in ethylhexyl triazone (EHT, octyl triazone), an approved ultraviolet-B (UV-B) chemical filter for commercial sunscreens, remain elusive, with a notable absence of ultrafast time-resolved measurements. These large organic molecules are of increasing interest as they are suspected to be less likely to penetrate the skin than some of the smaller approved filters, thereby reducing the possible adverse effects from sunscreen products. We apply femtosecond transient absorption spectroscopy with electronic structure calculations to unravel the complete photodeactivation mechanism that EHT undergoes after UV-B irradiation. We propose that this involves ultrafast internal conversion of the initially photoexcited n1ππ* state that couples to the ground state via a 11ππ*/S0 conical intersection, enabling multiple absorption and recovery cycles, as one would anticipate from a highly efficient filter. We also observe long-lived photoproducts which, based on previous studies along with present electronic structure calculations, we attribute to trapped excited populations in the S1 and T1 states.

Item Type:	Journal Article
Subjects:	Q Science > QC Physics Q Science > QD Chemistry
Divisions:	Faculty of Science, Engineering and Medicine > Science > Chemistry Faculty of Science, Engineering and Medicine > Science > Centre for Scientific Computing
Library of Congress Subject Headings (LCSH):	Photoabsorption, Spectrum analysis, Ultraviolet radiation, Photochemistry, Sunscreens (Cosmetics)
Journal or Publication Title:	The Journal of Physical Chemistry Letters
Publisher:	American Chemical Society
ISSN:	1948-7185
Official Date:	24 April 2017
Dates:	Date Event 24 April 2017 Published 24 April 2017 Accepted 15 March 2017 Submitted
Volume:	8
Number:	10
Page Range:	pp. 2113-2118
DOI:	10.1021/acs.jpclett.7b00633
Status:	Peer Reviewed
Publication Status:	Published
Access rights to Published version:	Open Access (Creative Commons)
Date of first compliant deposit:	10 April 2018
Date of first compliant Open Access:	10 April 2018
RIOXX Funder/Project Grant:	Project/Grant ID RIOXX Funder Name Funder ID EP/F500378/1 [EPSRC] Engineering and Physical Sciences Research Council http://dx.doi.org/10.13039/501100000266 EP/J007153 [EPSRC] Engineering and Physical Sciences Research Council http://dx.doi.org/10.13039/501100000266 UNSPECIFIED Royal Society http://dx.doi.org/10.13039/501100000288
Related URLs:	Related dataset

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