Visualizing competing intersystem crossing and internal conversion with a complementary measurement.

Content Provider	Semantic Scholar
Author	Liu, Yuzhu Gerber, Thomas Qin, Chaochao Jin, Feng Knopp, Gregor
Copyright Year	2016
Abstract	A complementary measurement method based on a home-built double-sided velocity map imaging setup is introduced. This method can simultaneously obtain time-resolved photoelectron imaging and fragment ion imaging. It has been successfully applied to investigate the ultrafast dynamics of the second singlet electronically excited state (S2) in m-xylene. Time-resolved photoelectron and ion signals derived from the initial populated S2 state are tracked following two-photon absorption of a pump pulse. Time-of-flight mass spectra (TOFMS) show that there are dominant parent ions and one fragment ions with methyl loss during such a process. According to the measured photoelectron images and fragment ions images, transient kinetic energy distributions and angular distributions of the generated photoelectrons and fragments are obtained and analyzed. Compared to stand-alone photoelectron imaging, the obtained fragment ion imaging is powerful for further understanding the mechanisms especially when the dissociation occurs during the pump-probe ionization. Two competing channels intersystem crossing T3←S2 and internal conversion S1←S2 are attributed to the deactivation of the S2 state. A lifetime of ∼50 fs for the initially excited S2 state, of ∼276 fs for the secondary populated S1 state, and of 5.76 ps for the T3 state is inferred.
Starting Page	084201
Ending Page	084201
Page Count	1
File Format	PDF HTM / HTML
DOI	10.1063/1.4942124
PubMed reference number	26931694
Journal	Medline
Volume Number	144
Issue Number	8
Alternate Webpage(s)	http://www.nccr-must.ch/libraries.files/liu-2016.pdf
Alternate Webpage(s)	https://doi.org/10.1063/1.4942124
Journal	The Journal of chemical physics
Language	English
Access Restriction	Open
Content Type	Text
Resource Type	Article