Ultrafast dynamics of fluorene initiated by highly intense laser fields.

We present an investigation of the ultrafast dynamics of the polycyclic aromatic hydrocarbon fluorene initiated by an intense femtosecond near-infrared laser pulse (810 nm) and probed by a weak visible pulse (405 nm). Using a multichannel detection scheme (mass spectra, electron and ion velocity-map imaging), we provide a full disentanglement of the complex dynamics of the vibronically excited parent molecule, its excited ionic states, and fragments. We observed various channels resulting from the strong-field ionization regime.

The kinetic energy of PAH dication and trication dissociation determined by recoil-frame covariance map imaging.

We investigated the dissociation of dications and trications of three polycyclic aromatic hydrocarbons (PAHs), fluorene, phenanthrene, and pyrene. PAHs are a family of molecules ubiquitous in space and involved in much of the chemistry of the interstellar medium. In our experiments, ions are formed by interaction with 30.

Ultrafast vibrational dynamics and energy transfer in imidazolium ionic liquids.

Femtosecond time-resolved coherent anti-Stokes Raman scattering (CARS) is used as a probe for monitoring the vibrational dynamics of room temperature ionic liquids (ILs). The experiments are performed on a series of 1,3-dialkylimidazolium ILs containing the bis(trifluoromethylsulfonyl)imide [NTf2] anion. The effect of methylation of the cationic C2 position on the dephasing time is studied analyzing [NTf2]-ILs of 1-ethyl-3-methylimidazolium [EMIM], 1-ethyl-2,3-dimethylimidazolium [EMMIM], 1-butyl-3-methylimidazolium [BMIM], and 1-butyl-2,3-dimethylimidazolium [BMMIM].

An unusual case of hematochezia: acute ischemic proctosigmoiditis.

Acute ischemia of the rectum is uncommon and usually occurs after aorto-iliac surgery. In this report, we present a case of acute ischemic proctosigmoiditis that developed from a brief episode of hypotension. An 85-year-old male presented to the emergency room with hypotension, mental confusion, and passage of maroon-colored stool.