Excimer states in microhydrated adenine clusters.

Citation data:

Physical chemistry chemical physics : PCCP, ISSN: 1463-9084, Vol: 12, Issue: 33, Page: 9632-6

Publication Year:
2010
Usage 10
Abstract Views 10
Captures 12
Readers 12
Citations 18
Citation Indexes 18
Repository URL:
http://scholarworks.unist.ac.kr/handle/201301/6237
PMID:
20556283
DOI:
10.1039/c003967e
Author(s):
Smith, V. R.; Samoylova, E.; Ritze, H. -H.; Radloff, W.; Schultz, Thomas
Publisher(s):
Royal Society of Chemistry (RSC); The Royal Society of Chemistry; ROYAL SOC CHEMISTRY
Tags:
Physics and Astronomy; Chemistry; RESOLVED PHOTOELECTRON-SPECTROSCOPY; EXCITED SINGLET-STATES; DNA-BASE HOMODIMERS; MOLECULAR-DYNAMICS; DOUBLE HELICES; AB-INITIO; FEMTOSECOND SPECTROSCOPY; ELECTRONIC-STRUCTURE; ENERGY-TRANSFER; PAIRS
article description
We present femtosecond pump-probe mass and photoelectron spectra for adenine (A) and microhydrated A(m)(H(2)O)(n) clusters. Three distinct relaxation processes of photoexcited electronic states were distinguished: in unhydrated A, relaxation of the optically bright pipi* state occurred via the dark npi* state with respective lifetimes of <0.1 and 1.3 ps. In microhydrated clusters A(H(2)O)(n), relaxation via the npi* state is quenched by a faster relaxation process, probably involving pisigma* states. For the predominantly hydrogen-bonded adenine dimer (A(2)), excited state relaxation is dominated by monomer-like processes. When the adenine dimer is clustered with several water molecules, we observe a nanosecond lifetime from excimer states in pi-stacked clusters. From the electron spectra we estimate adiabatic ionization potentials of 8.32 eV (A), 8.27 eV (A(H(2)O)(1)), 8.19 eV (A(H(2)O)(2)), 8.10 eV (A(H(2)O)(3)), 8.18 eV (A(2)), and 8.0 eV (A(2)(H(2)O)(3-5)).