Index of content:
Volume 125, Issue 2, 08 July 2006
Quantum-state resolved reaction dynamics at the gas-liquid interface: Direct absorption detection of product from125(2006); http://dx.doi.org/10.1063/1.2217016View Description Hide Description
Exothermic reactive scattering of F atoms at the gas-liquid interface of a liquid hydrocarbon (squalane) surface has been studied under single collision conditions by shot noise limited high-resolution infrared absorption on the nascent product. The nascent vibrational distributions are inverted, indicating insufficient time for complete vibrational energy transfer into the surfaceliquid. The rotational distributions are well fit with a two temperature Boltzmann analysis, with a near room temperature component and a second much hotter scattering component . These data provide quantum state level support for microscopic branching in the atom abstraction dynamics corresponding to escape of nascent from the liquid surface on time scales both slow and fast with respect to rotational relaxation.
125(2006); http://dx.doi.org/10.1063/1.2219444View Description Hide Description
Previously calculated resonance widths of the ground vibrational levels in the electronic states and , which belong to the Wulf band system of ozone, are significantly smaller than observed experimentally. We demonstrate that predissociation is drastically enhanced by spin-orbit coupling between and . Multistate quantum mechanical calculations using ab initiospin-orbit coupling matrix elements give linewidths of optically bright components of the right order of magnitude.
125(2006); http://dx.doi.org/10.1063/1.2221693View Description Hide Description
Electrical conduction in solid state disordered multilayers of non-redox proteins is demonstrated by two-terminal transport experiments at the nanoscale and by scanning tunneling microscopy (STM/STS experiments). We also show that the conduction of the biomolecular films can be modulated by means of a gate field. These results may lead to the implementation of protein-based three-terminal nanodevices and open important new perspectives for a wide range of bioelectronic/biosensing applications.
Design of infrared laser pulses for the deexcitation of highly excited homonuclear diatomic molecules125(2006); http://dx.doi.org/10.1063/1.2221932View Description Hide Description
We explore the possibility of using shaped infrared laser pulses to deexcite a homonuclear diatomic molecule from its highest vibrational state down to its ground vibrational state. The motivation for this study arises from the need to deexcite alkali metal dimers in a similar way so as to stabilize molecular Bose–Einstein condensates. We demonstrate that for the case of the molecule, where it is possible to evaluate all the necessary high accuracy ab initio data on the interaction of the molecule with an electric field, we are able to successfully design a sequence of infrared laser pulses to accomplish the desired deexcitation process in a highly efficient manner.
Counter-ion perturbation of the fragmentation pathways of multiply charged anions: Evidence for exit channel complexes on the fragmentation potential energy surfaces125(2006); http://dx.doi.org/10.1063/1.2219116View Description Hide Description
We report the first low-energy collisional excitation measurements and density functional theory calculations to characterize the ground statepotential energy surfaces of contact ion-pair complexes that contain multiply charged anions (MCAs). Excitation of and result in fragmentation products associated with decay of the isolated constituent dianions, revealing that the ground state ion-pair surfaces are dominated by the intrinsic characteristics of the MCA. This observation is important since it indicates that counter-ion complexation only weakly perturbs the electronic structure of an MCA. For , where the dianion decays with production of two ionic fragments, we observe evidence for the existence of a novel exit-channel complex corresponding to a polar KCN salt unit bound to the anion. The results described provide a basis for understanding the potential energy surfaces and fragmentation characteristics of other ion-pair complexes that involve MCAs.