Richard J. Saykally

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.

Fourier transform microwave spectrum of the propane–water complex: A prototypical water‐hydrophobe system.

Abstract: The Fourier transform microwave spectrum of the propane–water complex (C3H8–H2O) has been observed and analyzed This spectrum includes transitions assigned to propane complexed with both the ortho and para nuclear spin confirmations of water The rotational constants indicate that the vibrationally averaged structure has all four heavy atoms coplanar, with the water center of mass lying on or near the C2 axis of propane, inside the CCC angle, 376(±002) A from the propane center‐of‐mass, and 435(±002) A from the methylene carbon The projection of the electric dipole onto the a inertial axis of the complex (0732 D for the ortho state and 0819 D for the para state) indicates that one of the protons of the water subunit lies on the C2 axis of the propane monomer, which is also the axis connecting the subunit centers of mass The small projection of the dipole along the b axis (014 D for the ortho state and 038 D for the para state) is most consistent with an equilibrium structure in which all three atoms of the water lie in the CCC plane of propane, with torsional tunneling about the hydrogen bond occurring on the same time scale as the overall rotation The small internal rotation tunneling splittings that occur in the rotational spectrum of the propane monomer are not observed in the spectrum of the complex

Complete characterization of the (D2O)2 ground state: high Ka rotation-tunneling levels.

Abstract: We report the observation of extensive a- and c-type rotation-tunneling (RT) spectra of (D2O)2 for Ka = 0-4. These data allow quantification of molecular constants and tunneling splittings for a number of previously unobserved RT states of (D2O)2. The vibrational ground state has thus been characterized to energies as high as those of some of the intermolecular vibrations, and we present the first test of the VRT(ASP-W) potential at these high Ka states.

Velocity modulation laser spectroscopy of molecular ions

Abstract: 34 v = 1 ← 0 R branch infrared transitions in the X 2Π state of the HF+ molecular ion have been measured by velocity modulation laser absorption spectroscopy. Fluorine hyperfine structure was resolved for low J transitions. From a weighted fit of all available high resolution data, values were determined for the v = 0 and v = 1 fluorine hyperfine constants (except b(1)), λ-doubling parameters, rotational and centrifugal distortion constants and the vibrational band origin. Molecular expectation values derived from the hyperfine constants are compared to similar quantities for OH and NH-. An analysis is presented for the v = 0 proton hyperfine structure observed previously by laser magnetic resonance.

Cavity‐Ringdown Spectroscopy Studies of the B2Σ+←X2Σ+ System of AlO

Abstract: KEYWORDS: cavity-ringdown spectroscopy ¥ laser spectroscopy ¥ rotational spectroscopy ¥ vibrational spectroscopy Aluminum is the second most abundant metal in the Earth's crust and, in view of its appreciable cosmic abundance, it is also of interest in astrophysics. [1] The metal is frequently used as a rocket fuel and, as a result of both military launches and the space program, considerable amounts of aluminum oxide are annually introduced into the atmosphere, which makes its chemistry and effect upon atmospheric processes topics of considerable interest. Both the diatomic AlO [2±5] and the triatomic Al 2 O [6] oxides were previously studied by optical spectroscopy. The best known transition of the simplest oxide (AlO) is the B 2 S ‡ 2 X 2 S ‡ system, with an origin near 20 688 cm À1 , which has been investigated extensively both through theory [7] and experiment. [8] In the laboratory, the oxides have been prepared by a number of techniques, but mostly in various discharges or flames. [9] It has also been detected in the upper atmosphere after the release of organoaluminum compounds. [10±12] Two higher-lying states of AlO, denoted C 2 P and D 2 S ‡ , are known. Several years ago Towle et al. employed laser-induced fluorescence to examine the C 2 P 2 X 2 S ‡ transition [3] in some detail. The lowest excited state, A 2 P, has only been observed in absorption in low-temperature matrices by Knight and Weltner. In the most extensive study of the B 2 S ‡ 2 X 2 S ‡ system, Coxon and Naxakis produced the oxide by discharge through a flowing mixture of aluminum chloride and oxygen, and analyzed some 25 bands ranging up to v' ˆ 9 and v'' ˆ 6. [8] By fitting their data, they obtained the molecular constants of AlO for both states involved. They could also resolve the spin-rotation doubling of P-branch lines of some of the bands. Resolution was possible, depending on the signal-to-noise ratio for a given band, only for the higher P-branch lines above a certain minimum value ranging from J ˆ 15 ± 28. They found that the spin-doubling constants in the two S states are strongly correlated, so that only the difference g' À g'' could be determined. Based on their data they concluded that for the B state, g' exhibits only small linear variation with v', whereas in …

Fast parallel algorithms for short-range molecular dynamics

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.

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

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。

The Optical Properties of Metal Nanoparticles: The Influence of Size, Shape, and Dielectric 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...

Dye-Sensitized Solar Cells

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 ...

Quantum Dot Bioconjugates for Ultrasensitive Nonisotopic Detection

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.