Molecular coupling of light with plasmonic waveguides

We use molecules to couple light into and out of microscale plasmonic waveguides. Energy transfer, mediated by surface plasmons, from donor molecules to acceptor molecules over ten micrometer distances is demonstrated. Also surface plasmon coupled emission from the donor molecules is observed at similar distances away from the excitation spot. The lithographic fabrication method we use for positioning the dye molecules allows scaling to nanometer dimensions. The use of molecules as couplers between far-field and near-field light offers the advantages that no special excitation geometry is needed, any light source can be used to excite plasmons and the excitation can be localized below the diffraction limit. Moreover, the use of molecules has the potential for integration with molecular electronics and for the use of molecular self-assembly in fabrication. Our results constitute a proof-of-principle demonstration of a plasmonic waveguide where signal in- and outcoupling is done by molecules.Comment: 9 pages, 5 figure

Rotational isomerization of small carboxylic acids isolated in argon matrices: Tunnelling and quantum yields for the photoinduced processes

The quantum yields for internal rotation around the C–O bond induced by excitation of the first overtone of the hydroxyl stretching mode in formic, acetic, and propionic acids isolated in solid Ar are comparatively discussed. The tunnelling kinetics for isomerization from the higher energy arrangement of the carboxylic group (cis) to the lower energy arrangement (trans) in this series of compounds is also analysed. Finally, the quantum yield for the Cα–C isomerization in propionic acid was investigated and, in contrast with the C–O isomerization, shown to be probably sensitive to the local matrix morphology

Infrared-Induced Rotamerization of Oxalic Acid Monomer in Argon Matrix

Infrared-induced conformational isomerization of oxalic acid monomer isolated in an argon matrix at 7.5 K was studied by infrared spectroscopy. For the first time, three conformational states of this molecule were identified experimentally and their vibrational spectra are assigned. In good agreement with density functional theory predictions, all the observed conformers exhibit a trans OC−CO axis, differing in the relative conformation of their O−C−O−H axes. In the most stable conformer (belonging to the C2h symmetry point group), two intramolecular OH···O hydrogen bonds are present. The second (Cs) most stable conformer shows a single OH···O bond, and the third one (C2h) does not exhibit any intramolecular hydrogen bond. Using narrowband tunable irradiation in the near-infrared region it was possible to promote very efficiently conformer interconversions, which was followed spectroscopically

Kr–Cl stretching vibration of HKrCl: Matrix-isolation and anharmonic ab initio study

The Kr–Cl stretching vibration of HKrCl molecule is studied. The absorption shows ³⁵Cl and ³⁷Cl isotopic splitting due to natural abundance of the Cl isotopes. The observed Kr–Cl stretching vibrations of the HKrCl are at 253.1 (³⁵Cl) and 248.3 cm–¹ (³⁷Cl). Deuteration of the HKrCl does not cause experimentally a shift of the Kr–Cl stretching frequency. In addition to the Kr–Cl stretching mode, the bending mode of DKrCl is observed at 397.7 cm–¹. The vibrational analysis suggests that the Kr–Cl bond show, in addition to ionic, some covalent character. Anharmonic ab initio calculations are employed to verify vibrational properties of various isotopologues of HKrCl

Neutral rare-gas containing charge-transfer molecules in solid matrices : III. HXeCN, HXeNC, and HKrCN in Kr and Xe

Copyright (1998) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.The synthesis of novel rare-gas compounds HXeCN, HXeNC, and HKrCN is reported. HKrCN represents the first stable compound with a Kr–C bond. The novel molecules are formed in solid Xe and Kr by first photolyzing monomeric HCN with a 193 nm ArF laser at 7.5 K. The photolysis produces isolated hydrogen atoms and CN radicals as evidenced by IR spectroscopy and laser induced fluorescence. Annealing of the Kr matrix at ~ 30 K and Xe matrix at ~ 50 K activates the hydrogen atoms, and they react with rare-gas atoms surrounding the CN radicals producing the rare-gas compounds, which are characterized in this work by means of IR spectroscopy and ab initio calculations. Other products observed are HNC and H2CN. Infrared induced photochemical conversion of HXeNC to HXeCN is accomplished by exciting the Xe–H and C–N stretching fundamentals of HXeNC. The existence of low barrier between these two distinct isomers is confirmed by the ab initio calculations

Neutral rare-gas containing charge-transfer molecules in solid matrices : II. HXeH, HXeD, and DXeD in Xe

Copyright (1995) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.Photolysis of hydrogen halides (and some other hydrogen containing small molecules) in solid Xe yields in a two step process charged centers, one of them being XeHXe⁺. Annealing of the irradiated doped solids produces, in addition to H–Xe–Y (Y=Cl, Br, or I) species characterized by us previously, a fairly strong doublet at 1181 and 1166 cm⁻¹ and a weak absorption at 701 cm⁻¹. Deuterated precursors yield a doublet at 846 and 856 cm⁻¹. Also peaks belonging to mixed H/D form are found, indicating that the absorbing species contains two H/D atoms. The new species responsible for these absorptions are assigned as neutral linear centrosymmetric HXeH, HXeD, and DXeD. The nature of the bonding can be understood in terms of the resonance between the two ionic forms HXe⁺H⁻ and H⁻Xe⁺H, analogously to the valence bond description of the well known XeF₂. The pseudopotential (LANL1DZ) ab initio calculations at the MP2 level are in good agreement with the observed spectra. PACS: 34.70.﹢e, 82.50.Fv, 33.80.Gj, 82.30.F

Legal issues and underexplored data protection in medical 3D printing: A scoping review

Introduction: 3D printing has quickly found many applications in medicine. However, as with any new technology the regulatory landscape is struggling to stay abreast. Unclear legislation or lack of legislation has been suggested as being one hindrance for wide-scale adoption.Methods: A scoping review was performed in PubMed, Web of Science, SCOPUS and Westlaw International to identify articles dealing with legal issues in medical 3D printing.Results: Thirty-four articles fulfilling inclusion criteria were identified in medical/technical databases and fifteen in the legal database. The majority of articles dealt with the USA, while the EU was also prominently represented. Some common unresolved legal issues were identified, among them terminological confusion between custom-made and patient-matched devices, lack of specific legislation for patient-matched products, and the undefined legal role of CAD files both from a liability and from an intellectual property standpoint. Data protection was mentioned only in two papers and seems an underexplored topic.Conclusion: In this scoping review, several relevant articles and several common unresolved legal issues were identified including a need for terminological uniformity in medical 3D printing. The results of this work are planned to inform our own deeper legal analysis of these issues in the future