A5044410850- Advanced Chemical Physics Studies
- Quantum, superfluid, helium dynamics
- Spectroscopy and Laser Applications
- Cold Atom Physics and Bose-Einstein Condensates
- Synthetic Organic Chemistry Methods
- Catalytic Cross-Coupling Reactions
- Photochemistry and Electron Transfer Studies
- Spectroscopy and Quantum Chemical Studies
- Advancements in Photolithography Techniques
- X-ray Spectroscopy and Fluorescence Analysis
- Electron and X-Ray Spectroscopy Techniques
- Atmospheric Ozone and Climate
- Catalytic C–H Functionalization Methods
- Marine Sponges and Natural Products
- Mass Spectrometry Techniques and Applications
- Advanced NMR Techniques and Applications
- Chemical synthesis and alkaloids
- Protein Hydrolysis and Bioactive Peptides
- X-ray Diffraction in Crystallography
- Inorganic Fluorides and Related Compounds
- Various Chemistry Research Topics
- Laser-Matter Interactions and Applications
- Integrated Circuits and Semiconductor Failure Analysis
- Catalysis and Oxidation Reactions
- Oxidative Organic Chemistry Reactions
California State University, Fresno
2020-2025
University of California, Berkeley
2014-2021
Australian National University
2021
Lawrence Berkeley National Laboratory
2010-2018
Q Chem (United States)
2014
Smith College
2004-2009
A summary of the technical advances that are incorporated in fourth major release Q-Chem quantum chemistry program is provided, covering approximately last seven years. These include developments density functional theory methods and algorithms, nuclear magnetic resonance (NMR) property evaluation, coupled cluster perturbation theories, for electronically excited open-shell species, tools treating extended environments, algorithms walking on potential surfaces, analysis tools, energy...
This article summarizes technical advances contained in the fifth major release of Q-Chem quantum chemistry program package, covering developments since 2015. A comprehensive library exchange-correlation functionals, along with a suite correlated many-body methods, continues to be hallmark software. The methods include novel variants both coupled-cluster and configuration-interaction approaches based on algebraic diagrammatic construction variational reduced density-matrix methods. Methods...
X-ray vision catches Woodward-Hoffmann The celebrated (W-H) rules rationalize a variety of rapid bond rearrangements in organic molecules. key insight involved symmetry conservation the electronic journey from reactant to product. Attar et al. now report femtosecond x-ray absorption spectra and accompanying simulation studies that track shifts carbon states during one such reaction: photochemical ring opening cyclohexadiene hexatriene (see Perspective by Sension). smooth evolution occurs...
A one-semester physical chemistry course was fully redesigned with a modular structure to incorporate specifications grading system. The motivation for the redesign is discussed, and revised described. This taught once year, lessons learned from five implementations are highlighted (Fall semesters 2018–2022). Most of offerings were in-person, except virtual Fall 2020 iteration. Although there no significant difference in final grades found before after redesign, updated permitted more...
The dynamics resulting from electronic excitations of helium clusters were explored using ab initio molecular dynamics. simulations performed with configuration interaction singles and adiabatic classical coupled to a state-following algorithm. 100 different configurations He7 excited into the 2s 2p manifold for total 2800 trajectories. While most common outcome (90%) was complete fragmentation 6 ground state atoms 1 atom, 3% trajectories yielded bound,...
The aggregation of plasmonic nanoparticles can lead to new and controllable properties useful for numerous applications. We recently showed the reversible gold (AuNPs) via a small, cationic di-arginine peptide; however, mechanism underlying this is not yet comprehensively understood. Here, we seek insights into intermolecular interactions peptide-induced assembly citrate-capped AuNPs by empirically measuring how peptide identity impacts AuNP aggregation. examined nanoscale between peptides...
In order to increase computation power and efficiency, the semiconductor industry continually strives reduce size of features written using lithographic techniques. The planned switch a shorter wavelength extreme ultraviolet (EUV) source presents challenge for associated photoresists, which in their current manifestation show much poorer photoabsorption cross sections same dose. Here we consider critical role that an inner-shell electronic structure might play enhancing sections, one can...
New photoresists are needed to advance extreme ultraviolet (EUV) lithography. The tailored design of efficient is enabled by a fundamental understanding EUV induced chemistry. Processes that occur in the resist film after absorption an photon discussed, and new approach study these processes on level described. photoabsorption, electron emission, molecular fragmentation were studied experimentally gas-phase analogs monomer units employed chemically amplified resists. To demonstrate...
We studied the scope and limitations of a tandem intramolecular Nicholas/Pauson−Khand strategy for synthesis tricyclic oxygen- nitrogen-containing heterocycles. This methodology enables conversion simple acyclic starting materials into series previously unknown heterocyclic architectures. For preparation cyclic ethers (Z = O), [5,6,5]- through [5,9,5]-systems (m 1, n 1−4) are available with [5,7,5]- [5,8,5]-systems amenable to quick efficient synthesis. Tricyclic [5,8,5]-amine-containing...
We develop a local excited-state method, based on the configuration interaction singles (CIS) wave function, for large atomic and molecular clusters. This method exploits properties of absolutely localized orbitals (ALMOs), which strictly limits total number excitations, results in formal scaling with third power system size computing full spectrum ALMO-CIS excited states. The derivation equations design algorithm are discussed detail, particular emphasis computational scaling. Clusters...
The vertical excitation energies of small helium clusters, He(7) and He(25), have been calculated using configuration interaction singles, the character excited states was determined attachment/detachment density analysis. It found that in n = 2 manifold excitations could be interpreted as superpositions atomic states, with on surface clusters being lower energy than those bulk. For significant interior cluster, mixing 3 resulted energies. spatial extent excited-state can much larger size...
Phenylurea herbicides are widely used to control unwanted plant growth, but can linger in the environment. Photodegradation is a key mechanism by which these compounds be transformed. This paper investigates direct photoabsorption and relaxation of twelve phenylurea (chlorbromuron, chlortoluron, diuron, fenuron, fluometuron, isoproturon, linuron, methiuron, metobromuron, metoxuron, monolinuron, monuron) using density functional theory. Ground state structures treated at B3LYP-D3/def2-svp...
Simple acyclic enynes can be easily converted into tricyclic ethers upon treatment with Co2(CO)8 followed by Nicholas and Pauson−Khand reactions. Tricyclic [5,8,5]- [5,7,5]-systems prepared in high overall yields only seven synthetic steps.
Femtosecond extreme ultraviolet transient absorption spectroscopy is used to explore strong-field ionization induced dynamics in selenophene (C4H4Se). The are monitored real-time from the viewpoint of Se atom by recording temporal evolution element-specific spectral features near 3d inner-shell edge (∼58 eV). interpretation experimental results supported first-principles time-dependent density functional theory calculations. experiments simultaneously capture instantaneous population stable...
Simulations of the n = 2 absorption spectra HeN (N 70, 150, 231, 300) clusters are reported, with nuclear configurations sampled by path integral molecular dynamics. The electronic structure is treated a new approach, ALMO-CIS+CT, which formulation configuration interaction singles (CIS) based on absolutely localized orbitals (ALMOs). method generalizes previously reported ALMO-CIS model [K. D. Closser et al. J. Chem. Theory Comput. 11, 5791 (2015)] to include spatially charge transfer (CT)...
We have observed OH radical products from the unimolecular dissociation of ethyl hydroperoxide (CH3-CH2OOH) excited to 5nuOH and collected an action spectrum 15,600 16,800 cm(-1) product state distribution at maximum (16,119 cm(-1)). use a vibrational-torsional model simulate spectra in region for trans gauche conformers. A combination two simulated resembles experimental spectrum, provided that conformer is assumed dominate room temperature. Energy disposal fragment yields upper limit O-O...
Digold(<sc>i</sc>)–NHC complex catalyzes an intramolecular carboalkoxylation reaction of <italic>p</italic>-methoxybenzyl ethers 2-ethynylaryl phenols to give 2,3-disubstituted benzofurans in good yields.
We have developed a new strategy for the preparation of diolides using cascade Nicholas reactions. The carboxylic acid nucleophiles in these reactions are virtually unstudied participants transformations this type. Using methodology, 16-membered cobalt-complexed cyclic diyne is available 28% yield over eight steps (an average 85% per step). can also easily access uncomplexed diolide one additional step.
Abstract For see ChemInform in Full Text.