title: Ultrafast vibrational dynamics of adenine-thymine base pairs in DNA oligomers.
abstract: N-H stretching excitations of DNA oligomers containing 23 alternating adenine-thymine base pairs are studied in femtosecond two-color pump-probe experiments. For a DNA film in a zero relative humidity atmosphere, transient vibrational spectra and their time evolution up to 10 ps demonstrate negligible spectral diffusion and allow for discerning different N-H stretching bands and the O-H stretching absorption of residual water molecules. Lifetimes on the order of 0.5 ps are found for both N-H and O-H stretching modes. The time-dependent pump-probe anisotropies of the different N-H excitations point to a pronounced coupling among them, whereas the O-H stretching anisotropy remains essentially constant.
authors.affiliation: Max-Born-Institut für Nichtlineare Optik und Kurzzeitspektroskopie, Max-Born-Strasse 2 A, D-12489 Berlin, Germany.
authors.forename: Jason R
authors.initials: JR
authors.lastname: Dwyer
authors.forename: Lukasz
authors.initials: L
authors.lastname: Szyc
authors.forename: Erik T J
authors.initials: ET
authors.lastname: Nibbering
authors.forename: Thomas
authors.initials: T
authors.lastname: Elsaesser
mesh_terms: D000225:Adenine / Q000737:chemistry*; D001483:Base Sequence; D004247:DNA / Q000737:chemistry*; D009838:Oligodeoxyribonucleotides / Q000737:chemistry*; D013941:Thymine / Q000737:chemistry*; D014732:Vibration
chemical_list: D009838:Oligodeoxyribonucleotides; D004247:DNA; D000225:Adenine; D013941:Thymine