Search arXiv⌕ Search
Home/Archive/arXiv

arXiv · cond-mat/0508568

Polarization and Experimental Configuration Analysis of Sum Frequency Generation Vibrational Spectra of Air/Water Interface

Wei Gan·Dan Wu·Zhen Zhang·Ran-ran Feng·Hong-fei Wang
View original source ↗Read source document ↗Export metadata ↓

Abstract

Here we report a detailed study on spectroscopy, structure and dynamics of water molecules at air/water interface, investigated with Sum Frequency Generation Vibrational Spectroscopy (SFG-VS). Quantitative polarization and experimental configuration analysis of the SFG data in different polarizations with four sets of experimental configurations can shed new lights on our present understanding of the air/water interface. Firstly, we concluded that the motion of the interfacial water molecules can only be in a limited angular range, instead rapidly varying over a broad angular range in the vibrational relaxation time suggested previously. Secondly, because different vibrational modes of different molecular species at the interface has different symmetry properties, polarization and symmetry analysis of the SFG-VS spectral features can help assignment of the SFG-VS spectra peaks to different interfacial species. These analysis concluded that the narrow 3693cm-1 and broad 3550cm-1 peaks belong to C_ v symmetry, while the broad 3250cm-1 and 3450cm-1 peaks belong to the symmetric stretching modes with C_2v symmetry. Thus, the 3693cm-1 peak is assigned to the free OH, the 3550cm-1 peak is assigned to the single hydrogen bonded OH stretching mode, and the 3250cm-1 and 3450cm-1 peaks are assigned to interfacial water molecules as two hydrogen donors for hydrogen bonding (with C_2v symmetry), respectively. Thirdly, analysis of the SFG-VS spectra concluded that the singly hydrogen bonded water molecules at the air/water interface have their dipole vector direct almost parallel to the interface, and is with a very narrow orientational distribution. The doubly hydrogen bond donor water molecules have their dipole vector point away from the liquid phase.

Explore related subjects

cond-mat.other

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Wei Gan, Dan Wu, Zhen Zhang, Ran-ran Feng, Hong-fei Wang. 2005-08-24. Polarization and Experimental Configuration Analysis of Sum Frequency Generation Vibrational Spectra of Air/Water Interface. https://doi.org/10.1063/1.2179794

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

arXiv2026

Nanoscale Inclined Four-electrode Ion Traps: Finite-Element Modelling, Floquet Stability, and Surface-Potential Response

Developing miniaturised trapped-ion systems requires electrode architectures that provide controlled radio-frequency (RF) confinement while accounting for nanoscale features and surface-induced perturbations. Here, we present a finite-element investigation of an inclined four-blade RF ion-trap architecture for 171Yb+, combining pseudopotential characterisation, matrix Mathieu analysis, Floquet stability assessment, and localised surface-potential modelling. The architecture incorporates exposed electrode-face features of approximately 99-150 nm within an opposing-electrode separation of 20 um. At an electrode inclination of 6 degrees, an RF amplitude of 150 V, and a drive frequency of 15 MHz, the calculated pseudopotential exhibits directional in-plane barriers of 3.430 and 3.389 meV along the principal diagonal paths. The full RF-potential Hessian, including off-diagonal coupling terms, is used to construct the matrix Mathieu equation. Numerical propagation over one RF period identifies two dominant motional branches with secular-frequency estimates of 1.8137 and 1.8181 MHz. A third, predominantly axial branch exhibits a nominal frequency near 7.90 kHz, although its quantitative resolution is limited by the residual Hessian trace and phase-return drift. Additionally, a four-source electrostatic model is developed to investigate the effects of localised surface potentials on modal electric-field responses. Parametric analysis reveals correlation-dependent suppression and enhancement of normalised response coefficients, with multipliers ranging from approximately 0.5 to 1.5. This study establishes a computational framework for investigating nanoscale inclined blade-electrode architectures, their motional characteristics, and surface-potential responses, while highlighting numerical convergence requirements for reliable three-dimensional trap characterisation.

cond-mat.other↗
arXiv2026

Chiral-vibration-induced magnetism and circular dichroism in organic molecules

We investigate the vibrational inverse Faraday effect and transient vibrational circular dichroism in benzene, coronene, and methane at the single-molecule level. We combine density-functional tight-binding calculations with damped normal-mode dynamics. Circularly polarized light excites suitable degenerate infrared-active modes, driving chiral nuclear motion that produces effective magnetic moments. Reversing the pump helicity reverses the vibrational chirality and the sign of the transient dichroic response. These results support a writing-readout scheme in which circularly polarized pumping prepares a chiral vibrational state and transient vibrational circular dichroism probes its handedness. We further examine how molecular symmetry shapes the light-induced chiral response across the three molecular systems. This work provides a valuable platform for exploring all-optical control of magnetism and chiroptical probing at the molecular scale.

cond-mat.other↗
arXiv2026

A Construction Framework for Three-Dimensional Topological Magnetic Textures

Three-dimensional magnetic systems offer diverse possibilities for constructing complex topological textures from simpler magnetic configurations. Here, we present different routes for constructing complex three-dimensional magnetic textures from simpler parent configurations and discuss their impact on the topology of the resulting structures. We identify four construction principles: (i) adding transverse modulations, (ii) adding structures, (iii) entangling textures (e.g. braiding, or twisting), and (iv) introducing singularities. Using the skyrmion tube as an explicit parent configuration, we show how these principles give rise to several known three-dimensional magnetic textures. We then apply the same principles to predict novel textures derived from a meron tube, which are confirmed by micromagnetic simulations to be metastable in chiral magnets. Our results establish general principles for the systematic construction and discovery of complex three-dimensional magnetic textures.

cond-mat.other↗