Time-resolved photoelectron spectroscopy of adenosine and adenosine monophosphate photodeactivation dynamics in water microjets

• Published in: The Journal of chemical physics Vol. 148; no. 19; p. 194303
• Main Authors: Williams, Holly L, Erickson, Blake A, Neumark, Daniel M
• Format: Journal Article
• Language: English
• Published: United States 21.05.2018
• ISSN: 1089-7690
• DOI: 10.1063/1.5027258

The excited state relaxation dynamics of adenosine and adenosine monophosphate were studied at multiple excitation energies using femtosecond time-resolved photoelectron spectroscopy in a liquid water microjet. At pump energies of 4.69-4.97 eV, the lowest ππ excited state, S , was accessed and its decay dynamics were probed via ionization at 6.20 eV. By reversing the role of the pump and probe lasers, a higher-lying ππ state was excited at 6.20 eV and its time-evolving photoelectron spectrum was monitored at probe energies of 4.69-4.97 eV. The S ππ excited state was found to decay with a lifetime ranging from ∼210 to 250 fs in adenosine and ∼220 to 250 fs in adenosine monophosphate. This lifetime drops with increasing pump photon energy. Signal from the higher-lying ππ excited state decayed on a time scale of ∼320 fs and was measureable only in adenosine monophosphate.