This paper reports the results of a calculation of the optical response of a hexagonal lattice of Ag spheroids coated with confocal layers of dye. The layered spheroid polarizability and the local field, which includes the effects of interactions with the quartz substrate, are calculated in the electrostatic limit. Using experimental data for a 60-A mass thick annealed Ag island film to determine the Ag spheroid aspect ratio and assuming a Lorentz oscillator response for the dye, it is shown that the absorption spectrum can exhibit three or more resonances depending on the strengths of the dye dispersion and the particle interactions. By comparing the power absorbed in the dye layer to the peak power absorbed by an equal volume of dye laid on a quartz substrate, it is shown that an absorption enhancement of the order of 10 can be obtained even when the molecular absorption energy is separated from the Ag spheroid plasma resonance by an electron volt or more. The enhancement is due to the amplification by the Ag core of the electric fields associated with the driven modes of the dye layer.

We calculate the time-dependent decay of the surface-plasmon-coupled molecular fluorescence from a solution of diffusing dye molecules near a metal. Measurements of this signal for an ethanol solution of Tb acetylacetonate next to a Ag film agree well with the calculation when effects due to the non-local response of Ag are included.

Surface-plasmon resonance (SPR) on high-reflectivity metals is very sensitive to changes in the optical properties of the surface region, in particular, to the effects of adsorbed molecules. We excite the SPR on noble-metal films using the Kretschmann configuration and detect the SPR via the surface-roughness-scattered light. By modulating the angle of incidence of the exciting laser beam and using the electronically differentiated signals to track and monitor the resonance, we are able to measure, as a function of time, the complex dielectric constant of the film and the strength of the surface-roughness scattering. We use this technique to study the chemisorption of ${\mathrm{O}}_{2}$ on Cu and Ag where we are able to detect the presence of a fractional monolayer of physisorbed ${\mathrm{O}}_{2}$ on the Ag film after the chemisorption is essentially complete. Data on the optical constants obtained from the metal-vacuum interface of in situ grown Ag, Cu, and Au films are presented. We also present data on the strong physical adsorption of 1,2-dichloroethane on room-temperature Ag films. At elevated temperatures, the dichloroethane attacks and roughens the surface. The increased roughness allows us to establish an upper limit of 1% for the contribution of the roughness scattering to the width of the SPR on the clean Ag film.

The probability for direct energy transfer from a dye molecule to the surface plasmons (SP) on a nearby metal is calculated using the classical Sommerfeld model. For 600-nm emission from a dipole-oriented ⊥ to an Ag surface, the peak SP coupling probability is 93% at a distance of 120 nm from the metal. The coupling is demonstrated in experiments with an Ag film between a rhodamine–methanol solution and a high-index prism. The SP-coupled radiation produces an intense cone of radiation in the prism, each frequency component of which satisfies the SP dispersion relation.

In this paper we present a general method for calculating the transfer and transmission functions of a cylindrical mirror analyzer (CMA) which employs the exact, albeit numerical, solutions of the particle equations of motion. The analysis incorporates emission from extended sources and easily lends itself for use with elements which preretard the particle’s kinetic energy. Our approach leads directly to a convenient display of the analyzer transmission in energy-angle space which provides a vantage point for assessing the role of each CMA aperture in the transmission process and for assessing the influence of the angular distribution of the emitted particles on the energy transfer function. The general method can be extended to include any dispersive analyzer for which the particle equations of motion are solvable.

Atomic ordering in bulk austenitic single-crystal samples of composition Fe-31 at.% Ni was investigated using x-ray and neutron diffraction techniques. Samples were annealed between 450–550 °C for time periods between 1.5 h and 55 days. No superlattice peak was observed in any case providing no evidence of long-range order in these samples. X-ray studies on martensitic samples of the same composition revealed a tetragonality of about 0.4% which was increased insignificantly by the ’’ordering’’ heat treatment given to the austenite prior to the martensitic transformation. If martensite tetragonality is linearly related to the difference in the first and second short-range order parameters of the austenite (as seems likely in this alloy) this observation supports and extends the results of the studies on the austenitic single crystals.

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTCrystal structure of KCP(Br) [K2Pt(CN)4Br0.30.3.2H2O] as determined by 300.deg.K x-ray and 8.deg.K neutron diffraction investigationsC. Peters and C. F. EagenCite this: Inorg. Chem. 1976, 15, 4, 782–788Publication Date (Print):April 1, 1976Publication History Published online1 May 2002Published inissue 1 April 1976https://pubs.acs.org/doi/10.1021/ic50158a008https://doi.org/10.1021/ic50158a008research-articleACS PublicationsRequest reuse permissionsArticle Views109Altmetric-Citations26LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-AlertscloseSupporting Info (1)»Supporting Information Supporting Information Get e-Alerts

In this paper we introduce the concept of flexible and rigid response of a molecular unit to a charge density wave (CDW) in the electron gas. We show that the CDW satellite reflections observed in a neutron-diffraction study at 7 K on a single crystal of ${\mathrm{K}}_{2}$Pt${(\mathrm{CN})}_{4}$${\mathrm{Br}}_{0.3}$.3.2${\mathrm{D}}_{2}$O (KCP) can be adequately explained by a rigid sinusoidal displacement of the Pt(${\mathrm{C}\mathrm{N})}_{4}$ complexes in response to the CDW instability in the ${d}_{{z}^{2}}$ band formed from the Pt atoms. The amplitude of the displacement wave is determined to be $(0.0047\ifmmode\pm\else\textpm\fi{}0.0005)\stackrel{\ensuremath{\rightarrow}}{\mathrm{c}}$, where $\stackrel{\ensuremath{\rightarrow}}{\mathrm{c}}$ is the lattice parameter, 5.692 \AA{} at 7 K, parallel to the Pt${(\mathrm{CN})}_{4}$hains.

As a result of detailed room-temperature x-ray diffraction, liquid-helium-temperature neutron diffraction, and thermal gravimetric studies, we have identified a third water molecule in the tetragonal unit cell of KCP. The full complement of waters of hydration is 3.2, and thus, the correct chemical formula is ${\mathrm{K}}_{2}$Pt${(\mathrm{CN})}_{4}$${\mathrm{Br}}_{0.30}$\ifmmode\cdot\else\textperiodcentered\fi{}3.2${\mathrm{H}}_{2}$O. Structurally, the additional water occupies those unit cells where the Br ion is absent, and therefore, it should be termed a disordered "defect water"; it clearly contributes to the stability of the crystal.

A neutron diffraction investigation on a single crystal of chromium, which is approximately single-Q, confirms the existence of a sinusoidal atomic displacement wave in the antiferromagnetic state. The wave is observed to be polarized parallel to the spin density wave (SDW) wavevector, Q, and to have a wavevector 2Q in both the transversely and longitudinally polarized SDW phases. The amplitude of the displacement wave is found to be proportional to the square of the amplitude of the SDW. We obtain for the displacement wave amplitude (0.0017 ± 0.0002)a at 130 K, where a is the lattice parameter.

We have directly observed the sign reversal of the wave function of a fermion produced by its precession of 2π radians in a magnetic field using a neutron interferometer.Received 27 August 1975DOI:https://doi.org/10.1103/PhysRevLett.35.1053©1975 American Physical Society

A neutron investigation on a chromium single crystal, which is 80% single‐Q̄, has confirmed the existence of the sinusoidal lattice displacement observed below the Néel temperature by Tsunoda et al1 with x rays. The displacement wave was found to have its polarization parallel to the spin density wavevector, Q̄, and to have wavevector 2Q̄ in both the longitudinally and transversely polarized spin density wave phases. Characteristic of a small sinusoidal lattice wave, the measured intensities of the 2Q̄ satellite peaks near the (1,1,0), and of the satellite peak below (1,1,0) at 130K, 248K, and 268K indicates that the displacement amplitude scales with the square of the magnetization as a function of temperature. Normalization of the various satellite peaks to the main nuclear and magnetic reflections yields a self‐consistent value for the displacement amplitude, ‐a/a, of (0.17±.02) % at 130K. This value appears to be significantly lower than the (0.25±/−5) % value obtained in the x‐ray investigation. One possible explanation for the discrepancy is that neutrons measure the periodic displacement of the nuclei while x rays are sensitive to both periodic displacements and periodic distortions of the atomic electron distribution.