The interfacial region of aqueous systems also known as the electrical double layer can be characterized on molecular level with second harmonic and sum-frequency generation (SHG/SFG). SHG SFG are surface specific methods for isotropic liquids. Here, we model SHG/SFG intensity in reflection, transmission, scattering geometry taking into account spatial variation all fields. We show that, presence a electrostatic field, interference effects, which originate from oriented water molecules...

Small aluminum nanoparticles have the potential to exhibit localized surface plasmon resonances in deep ultraviolet region of electromagnetic spectrum, however technical and scientific challenges make it difficult attain this limit. We report fabrication arrays Al/Al2O3 core/shell with a metallic-core diameter between 12 25 nm that display sharp plasmonic at very high energies, up 5.8 eV (down λ = 215 nm). The were fabricated by means straightforward self-organization approach. experimental...

Surface-specific vibrational sum-frequency generation spectroscopy (V-SFG) is frequently used to obtain information about the molecular structure at charged interfaces. Here, we provide experimental evidence that not only screening of surface charges but also interference limits extent which V-SFG probes interfacial water sub-mM salt concentrations. As a consequence, yields ∼single monolayer region very high ionic strength, where charge effectively screened, for pure due particularly large...

The electrical charge of biological membranes and thus the resulting alignment water molecules in response to this are important factors affecting membrane rigidity, transport, reactivity. We tune surface density by varying lipid composition investigate charge-induced using surface-specific vibrational spectroscopy molecular dynamics simulations. At low densities, increases proportionally charge. However, already at moderate, physiologically relevant starts saturate despite increase nominal...

Abstract Biomolecular condensates, protein-rich and dynamic membrane-less organelles, play critical roles in a range of subcellular processes, including membrane trafficking transcriptional regulation. However, aberrant phase transitions intrinsically disordered proteins biomolecular condensates can lead to the formation irreversible fibrils aggregates that are linked neurodegenerative diseases. Despite implications, interactions underlying such remain obscure. Here we investigate role...

We report on a high-resolution X-ray photoemission spectroscopy study molecular-thick layers of l-cysteine deposited under ultrahigh vacuum conditions Au(110). The analysis core level shifts allowed us to distinguish unambiguously the states first-layer molecules from those belonging second layer. strongly interact with metal through their sulfur headgroup. multipeaked structure N 1s, O and C 1s levels is interpreted in terms different molecular moieties. neutral acidic fraction...

The electrostatic environment of aqueous systems is an essential ingredient for the function any living system. To understand properties and their molecular foundation in soft, living, three-dimensional systems, we developed a table-top model-free method to determine surface potential nano- microscopic objects solutions. Angle-resolved nonresonant second harmonic (SH) scattering measurements contain enough information unambiguously, without making assumptions on structure interfacial region....

Because properties of colloids containing micro- and nano-particles are much influenced by the structure of, interactions occurring at, particle surface, it is important to be able characterize surface in situ nondestructively. Nonlinear light scattering from colloidal particles has been developed into a powerful versatile technique for characterizing surfaces since first demonstration detection second harmonic generation molecules adsorbed on micrometer-sized Eisenthal co-workers (Wang, H.;...

For well over a century, Hans Christian Gram's famous staining protocol has been the standard go-to diagnostic for characterizing unknown bacteria. Despite continuous and ubiquitous use, we now demonstrate that current understanding of molecular mechanism this differential stain is largely incorrect. Using fully complementary time-resolved methods: second-harmonic light-scattering bright-field transmission microscopy, present real-time membrane specific quantitative characterization...

The interfacial electrical potential is an important parameter influencing, for instance, electrochemical reactions and biomolecular interactions at membranes. A deeper understanding of different methods that measure quantities related to the surface thus great scientific technological relevance. We use lipid monolayers with varying charge density thoroughly compare results measurements performed vibrating plate capacitor method second harmonic generation spectroscopy. two techniques provide...

The increasing demand for heterogeneous materials prompts the interest physics and chemistry of organic–inorganic interfaces. Within this field we have investigated electronic states L-cysteine (Cys) adsorbed on Au(111) from aqueous solution with synchrotron-based, high resolution X-ray photoemission spectroscopy. analysis S 2p core level region in pristine samples prepared purified Cys indicates that adsorbs gold as a thiolate. absence signal related to physisorbed sulfur forms...

We have investigated the correlation between morphology and magnetic anisotropy in nanostructured Co films on Cu(001). The formation of nanoscale ripples by ion erosion is found to deeply affect properties film. A surface-type uniaxial with easy axis parallel observed. origin has been identified modification thermodynamic-step distribution induced ripple formation. At higher doses, when detach crystalline nanowires form, a strong enhancement due magnetostatic contributions

The size of the colloidal particle has a dramatic effect on efficiency optical second harmonic generation (SHG) from surface. This is illustrated with intensity measured submicrometer polystyrene beads adsorbed malachite green dye molecules in aqueous solution, both forward direction and as function scattering angle horizontal plane. In direction, SHG initially increases rapidly size. peaks at approximately 1 mum diameter then decreases majority SH light generated surface scatters away for...

The Rayleigh−Gans−Debye model, adapted for nonlinear optical phenomena, is used to describe the second harmonic scattering from surface of spherical particles in colloids. Specifically, effect size particle on efficiency generation Malachite Green (MG) molecules adsorbed polystyrene examined. model found be adequate describing patterns smaller with diameters ≤200 nm, but less so larger approaching 1 μm. From fit experimentally measured data (Part I this series, J. Phys. Chem. A 2009, 113,...

The localized surface plasmon resonance of metal nanoparticles allows confining the eletromagnetic field in nanosized volumes, creating high-field "hot spots", most useful for enhanced nonlinear optical spectroscopies. commonly employed metals, Au and Ag, yield resonances only spanning visible/near-infrared range. Stretching upward, energy range plasmonics requires exploiting different materials. Deep-ultraviolet happen to be achievable with one cheapest abundant materials available:...

Although second harmonic generation is intrinsically sensitive for probing interfaces, interpreting experimental observations the determination of interfacial properties colloidal particles requires rigorous theoretical treatment. A generally applicable nonlinear Mie theory expanded into higher multipolar terms describing scattering from surface spherical particles. From a least-square fitting angular distribution light molecules adsorbed on surface, we demonstrate molecular...

Even though nanoparticles have dimensions much smaller than the optical wavelength and shapes commonly with inversion symmetry, we show, for first time, direct experimental evidence that second harmonic generation (SHG) can be detected from surface layer of metallic nanoparticles, in this case 40 nm radius Ag particles. The SH intensity is shown to substantially decrease upon chemical bonding thiol molecules particle surface. generated used probing properties processes at nanoparticle

Development of new materials for drug delivery and biosensing requires the fine-tuning interfacial properties. We report here influence poly(ethylene glycol) (PEG) grafting density in model phospholipid monolayers on adsorption behavior bovine serum albumin human fibrinogen, not only with respect to amount adsorbed protein, but also its orientational ordering surface. As expected, increasing PEG density, protein decreases up point where complete repellency is reached. However, at...

Aminophosphonates were chosen for a first step functionalization of TiO2 grown on titanium, as they possess phosphonate group one end, that can be exploited coupling with the oxide surface, and an amino other end to enable further surface. The deposition aminophosphonates different chain lengths (6 12 methylenes) was investigated. Oxygen plasma treatment proved useful in increasing number −OH groups at thus helping anchor aminophosphonates. By combining surface-sensitive experimental...

To facilitate second-harmonic light scattering as an effective tool for sensing and imaging nanoparticles, a fundamental understanding of how particle properties affect the nonlinear process is necessary. The angle-resolved second harmonic patterns, measured in various polarization combinations, from spheroidal Ag particles (80 nm diameter) are presented first time compared with those similarly sized spherical polystyrene adsorbed nonlinear-optically active malachite green molecules....

Protein condensation into liquid-like structures is critical for cellular compartmentalization, RNA processing, and stress response. Research on protein has primarily focused membraneless organelles in the absence of lipids. However, cytoplasm full lipid interfaces, yet comparatively little known about how lipids affect condensation. Here, we show that nonspecific interactions between disordered fused sarcoma low-complexity (FUS LC) domain strongly In presence anionic lipids, FUS LC formed...