This review summarizes recent developments in the investigation of the electronic structures, spectroscopic properties, and reactivities of ferrous and ferric heme-nitrosyls and how this relates to important biological processes. Ferrous heme-nitrosyls show interesting variations in electronic structure as a function of the different types of proximal ligands, as is evident from electron parama...

The H and D atom elimination mechanisms in the photodissociation of jet cooled pyrrole and pyrrole-d1 have been studied by photofragment velocity map imaging. The molecules were excited to the 1 1A2 (pi sigma*) state at lambda = 243 nm and to the 1 1B2 (pi pi*) state at lambda = 217 nm. H/D atoms were detected by (2 + 1) resonance enhanced multiphoton ionization (REMPI) at lambda = 243 nm. The ...

Although electrons having enough energy to ionize or electronically excite DNA have long been known to cause strand breaks (i.e., bond cleavages), only recently has it been suggested that even lower-energy electrons (most recently 1 eV and below) can also damage DNA. The findings of the present work suggest that, while DNA bases can attach electrons having kinetic energies in the 1 eV range and...

Introduction: Bacteria have at least one sigma factor (σ-factor) that transcribes the genes required for cell viability. Usually, transcription of σ-factors occurs and changes in response to a variety of environmental stresses. Expression of σ-factors is one of the strategies which is used in response to different stress conditions. This study was aimed to evaluate the effects...

We report the first structural characterization of the triplet isomer of C6. Forty-one rovibrational/fine structure transitions in the nu 4(sigma u) antisymmetric stretch fundamental of the C6 cluster have been measured by diode laser absorption spectroscopy of a supersonic carbon cluster beam. The observed spectrum is characteristic of a centrosymmetric linear triplet state with cumulene-type ...

The presence of a delocalized pi-bond is often considered an essential criterion for achieving planar hypercoordination. Herein, we show that sigma-delocalization could be sufficient to make the configuration the...

A high-level computational study using CCSD, CCSD(T), and G2(+) levels of theory has shown that unactivated vinyl substrates such as vinyl chloride would afford gas phase, single-step halide exchange by a pure in-plane sigma-approach of the nucleophile to the backside of the C--Cl sigma bond. Geometry optimization by CCSD/6-31+G* and CCSD(T)/6-31+G* confirms the earlier findings of Glukhovtsev,...

The cavity ringdown technique (CRLAS) has been employed to measure the gas phase absorption spectrum of the platinum silicide molecule in the 350 nm region. All nine of the measured rovibronic bands are assigned to a single 1 sigma-1 sigma electronic transition, with a ground state vibrational frequency of omega "e = 549.0(3) cm-1, and a bond length of r"0 = 2.069(1) angstroms. The results of...