Author
Richard J. Saykally
Other affiliations: University of California, Lawrence Berkeley National Laboratory, University of California, Los Angeles ...read more
Bio: Richard J. Saykally is an academic researcher from University of California, Berkeley. The author has contributed to research in topics: Spectroscopy & Absorption spectroscopy. The author has an hindex of 94, co-authored 457 publications receiving 40997 citations. Previous affiliations of Richard J. Saykally include University of California & Lawrence Berkeley National Laboratory.
Papers published on a yearly basis
Papers
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TL;DR: Comparison with DFT computed spectra of model methanol clusters indicates that the bulk liquid comprises long chains and rings of hydrogen-bonded monomers.
Abstract: We have measured the X-ray absorption (XA) spectrum of liquid (298 K) methanol at the oxygen and carbon K edges. The 4a1 orbital at the O K edge exhibits a pronounced sensitivity to the formation of intermolecular hydrogen bonds, with significant differences observed between the vapor and bulk spectra, whereas the C K edge reveals only subtle corresponding spectral changes. Comparison with DFT computed spectra of model methanol clusters indicates that the bulk liquid comprises long chains (n > 6) and rings of hydrogen-bonded monomers.
81 citations
TL;DR: In this paper, the results of an extensive study of the ν3 (asymmetric stretch) vibration of the H3O+ ion were reported, and a total of 86 and 41 transitions were measured with a precision of 0.002 cm−1 for the s−s and a−a inversion subbands, respectively, and least squares fit to an accurate Hamiltonian.
Abstract: The results of an extensive study of the ν3 (asymmetric stretch) vibration of the H3O+ ion are reported. A total of 86 and 41 transitions were measured with a precision of 0.002 cm−1 for the s–s and a–a inversion subbands, respectively, and least‐squares fit to an accurate Hamiltonian. Twenty‐four parameters were determined in the analysis. The ν3 frequencies are 3535.974(11) and 3519.397(25) cm−1 for the s–s and a–a inversion components, respectively.
80 citations
TL;DR: These results comprise the most extensive vibrational spectroscopic study yet performed on metal ion hydration in the gas phase and provide insights into metal ion solvation in bulk and interfacial environments.
Abstract: Infrared laser action spectroscopy is used to characterize divalent calcium ions solvated by up to 69 water molecules. The spectrum for Ca2+(H2O)12 indicates that in the predominant structure, eight inner-shell water molecules solvate the metal ion and donate one hydrogen bond to one of four second-shell, double-acceptor water molecules. Eight-coordinate solvation is consistent with results from many condensed-phase studies, and contrasts with results for smaller gas-phase clusters that are most consistent with six-coordinate solvation. Each water molecule in this structure of Ca2+(H2O)12 coordinates with two other members of the cluster. With increasing cluster size, the number of two-coordinate water molecules decreases, whereas that of three-coordinate water molecules increases. The number of one-coordinate water molecules increases until n ≈ 18, but they are essentially depleted by n ≈ 30. Spectra of the largest clusters, which have effective concentrations of divalent calcium that are less than 1 M, ...
80 citations
TL;DR: In this article, a pulsed slit valve was used for generating supersonically cooled species in a long path length planar expansion. But the performance of the pulsed valve was limited to 12 hours, and operation over one month is typical before major maintenance.
Abstract: We report the design and performance of a pulsed slit valve for generation of supersonically cooled species in a long path length planar expansion. Utilizing three commercial solenoids driven synchronously by an economic power transistor circuit, the valve produces pulses adjustable in width from 500 to 1000 μs with a repetition rate up to 80 Hz. The pulsed valve can be operated continuously for 12 h, and operation over one month is typical before major maintenance is required. The path length × density product attained by this pulsed source is sufficient for observing large cluster species, such as the water hexamer, on our far‐infrared spectrometer. With the addition of a detachable sample oven, it can also be heated up to 230 °C to inject nonvolatile molecules into planar supersonic expansions.
80 citations
TL;DR: The emerging field of coherent nonlinear near-field scanning optical microscopy (NSOM) is reviewed in this article. But the authors focus on the nonlinear nonlinear NSOM with a focus on chemical selectivity, which is generated via resonant enhancement of nonlinear signals.
Abstract: The emerging field of coherent nonlinear near-field scanning optical microscopy (NSOM) is reviewed. Second harmonic, third harmonic, and sum frequency generation (SHG, THG, and SFG) are explored as means of providing chemically and environmentally selective probes with nanometer spatial resolution provided by scanning probe microscopy. Chemical selectivity is generated via resonant enhancement of the nonlinear signals, whereas interface vs bulk contrast is achieved by the order (even vs odd) of the optical process. A method of producing higher spectral resolution, and thus increased chemical selectivity, is also demonstrated in the form of near-field detected multiplex (or “broad-bandwidth”) SFG (MSFG). Applications to biological and material samples are described.
78 citations
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01 May 1993
TL;DR: Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems.
Abstract: Three parallel algorithms for classical molecular dynamics are presented. The first assigns each processor a fixed subset of atoms; the second assigns each a fixed subset of inter-atomic forces to compute; the third assigns each a fixed spatial region. The algorithms are suitable for molecular dynamics models which can be difficult to parallelize efficiently—those with short-range forces where the neighbors of each atom change rapidly. They can be implemented on any distributed-memory parallel machine which allows for message-passing of data between independently executing processors. The algorithms are tested on a standard Lennard-Jones benchmark problem for system sizes ranging from 500 to 100,000,000 atoms on several parallel supercomputers--the nCUBE 2, Intel iPSC/860 and Paragon, and Cray T3D. Comparing the results to the fastest reported vectorized Cray Y-MP and C90 algorithm shows that the current generation of parallel machines is competitive with conventional vector supercomputers even for small problems. For large problems, the spatial algorithm achieves parallel efficiencies of 90% and a 1840-node Intel Paragon performs up to 165 faster than a single Cray C9O processor. Trade-offs between the three algorithms and guidelines for adapting them to more complex molecular dynamics simulations are also discussed.
29,323 citations
28 Jul 2005
TL;DR: PfPMP1）与感染红细胞、树突状组胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作�ly.
Abstract: 抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。
18,940 citations
TL;DR: In this paper, the authors describe recent progress in the theory of nanoparticle optical properties, particularly methods for solving Maxwell's equations for light scattering from particles of arbitrary shape in a complex environment.
Abstract: The optical properties of metal nanoparticles have long been of interest in physical chemistry, starting with Faraday's investigations of colloidal gold in the middle 1800s. More recently, new lithographic techniques as well as improvements to classical wet chemistry methods have made it possible to synthesize noble metal nanoparticles with a wide range of sizes, shapes, and dielectric environments. In this feature article, we describe recent progress in the theory of nanoparticle optical properties, particularly methods for solving Maxwell's equations for light scattering from particles of arbitrary shape in a complex environment. Included is a description of the qualitative features of dipole and quadrupole plasmon resonances for spherical particles; a discussion of analytical and numerical methods for calculating extinction and scattering cross-sections, local fields, and other optical properties for nonspherical particles; and a survey of applications to problems of recent interest involving triangula...
9,086 citations
TL;DR: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency as mentioned in this paper, and many DSC research groups have been established around the world.
Abstract: Dye-sensitized solar cells (DSCs) offer the possibilities to design solar cells with a large flexibility in shape, color, and transparency. DSC research groups have been established around the worl ...
8,707 citations
TL;DR: Highly luminescent semiconductor quantum dots (zinc sulfide-capped cadmium selenide) have been covalently coupled to biomolecules for use in ultrasensitive biological detection and these nanometer-sized conjugates are water-soluble and biocompatible.
Abstract: Highly luminescent semiconductor quantum dots (zinc sulfide-capped cadmium selenide) have been covalently coupled to biomolecules for use in ultrasensitive biological detection. In comparison with organic dyes such as rhodamine, this class of luminescent labels is 20 times as bright, 100 times as stable against photobleaching, and one-third as wide in spectral linewidth. These nanometer-sized conjugates are water-soluble and biocompatible. Quantum dots that were labeled with the protein transferrin underwent receptor-mediated endocytosis in cultured HeLa cells, and those dots that were labeled with immunomolecules recognized specific antibodies or antigens.
7,393 citations