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The possibility of speech processing in the absence of an intelligible acoustic signal has given rise to the idea of a 'silent speech' interface , to be used as an aid for the speech-handicapped, or as part of a communications system operating in silence-required or high-background noise environments. The article first outlines the emergence of the silent(More)
We present experimental and theoretical evidence for an excited-state deactivation mechanism specific to hydrogen-bonded aromatic dimers, which may account, in part, for the photostability of the Watson-Crick base pairs in DNA. Femtosecond time-resolved mass spectroscopy of 2-aminopyridine clusters reveals an excited-state lifetime of 65 +/- 10 picoseconds(More)
Ab initio calculations and time-resolved photoionization spectroscopy were carried out to characterize the role of the lowest two pi sigma* excited states for the photoinduced processes in the adenine monomer, adenine dimer, and adenine-water clusters. The calculations show--with respect to the monomer--a stabilization of 0.11-0.14 eV for the pi sigma*(More)
" What is not surrounded by uncertainty cannot be the truth. "-Richard Feynman " True genius resides in the capacity for evaluation of uncertain, hazardous, and conflicting information. Abstract The goal of visualization is to effectively and accurately communicate data. Visualization research has often overlooked the errors and uncertainty which accompany(More)
Time-resolved photoelectron spectroscopy was used to study the energetics and dynamics of solvated electrons in aqueous solution. Solvated electrons are generated by ultrafast photodetachment in a 100 mM aqueous NaI solution. Initially, an ensemble of strongly bound ("cold") solvated electrons and an ensemble of weakly bound ("hot") electrons in an(More)
The excited-state dynamics of trans-azobenzene were investigated by femtosecond time-resolved photoelectron spectroscopy and ab initio molecular dynamics. Two near-degenerate pipi* excited states, S2 and S3,4, were identified in a region hitherto associated with only one excited state. These results help to explain contradictory reports about the(More)
We present a novel setup for the investigation of ultrafast dynamic processes in a liquid jet using time-resolved photoelectron spectroscopy. A magnetic-bottle type spectrometer with a high collection efficiency allows the very sensitive detection of photoelectrons emitted from a 10 μm thick liquid jet. This translates into good signal/noise ratio and rapid(More)
The structure and dynamics of the C (2)A(2) electronically excited state of the benzyl radical, C(7)H(7), were investigated by nanosecond and femtosecond pump-probe photoionization. A free jet of benzyl radicals was generated by flash pyrolysis from the precursors 2-phenylethyl nitrite and toluene. Nanosecond multiphoton ionization spectra show a number of(More)
The excited state decay of the hydrocarbon radicals ethyl, C(2)H(5); propargyl, C(3)H(3); and benzyl, C(7)H(7) was investigated by femtosecond time-resolved photoionization. Radicals were generated by flash pyrolysis of n-propyl nitrite, propargyl bromide, and toluene, respectively. It is shown that the 2 (2)A(') (3s) Rydberg state of ethyl excited at 250(More)
Time-resolved photoelectron spectroscopy at low kinetic energies (≲5 eV) is applied to dilute iodide solutions with different surface and bulk contributions. The results indicate a pronounced surface sensitivity. Signals assigned to solvated electrons near the liquid surface decay rapidly on a sub-ps timescale. In contrast to the literature, a long-lived(More)