A5001114553- Advanced Chemical Physics Studies
- Spectroscopy and Quantum Chemical Studies
- Quantum, superfluid, helium dynamics
- Polyoxometalates: Synthesis and Applications
- Quantum Dots Synthesis And Properties
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Spectroscopy and Laser Applications
- Molecular Spectroscopy and Structure
- Chalcogenide Semiconductor Thin Films
- Molecular Junctions and Nanostructures
- Advanced Nanomaterials in Catalysis
- Inorganic Fluorides and Related Compounds
- Atomic and Molecular Physics
- Crystallography and molecular interactions
- Metal-Organic Frameworks: Synthesis and Applications
- Catalytic C–H Functionalization Methods
- Advanced Photocatalysis Techniques
- Advanced NMR Techniques and Applications
- Catalytic Processes in Materials Science
- Photochemistry and Electron Transfer Studies
- Radioactive element chemistry and processing
- Perovskite Materials and Applications
- Semiconductor Quantum Structures and Devices
- Vanadium and Halogenation Chemistry
Atlanta University Center
2014-2025
Emory University
2014-2025
Emerson (United States)
2012-2024
AID Atlanta
2014-2020
University of Basel
2010
Lawrence Berkeley National Laboratory
2003-2004
Center for Theoretical Biological Physics
2003-2004
We report three modifications to recent ab initio, full-dimensional potential energy surfaces (PESs) for the water dimer [X. Huang et al., J. Chem. Phys. 128, 034312 (2008)]. The first modification is a refit of initio electronic energies produce an accurate dissociation D(e). second adds replacing monomer component PES with spectroscopically one and third produces hybrid that goes smoothly in asymptotic region flexible, Thole-type model potential, version 3 (denoted TTM3-F) [G. S....
Monoprotected chiral amino acids have recently been established as a class of ligand scaffolds for effecting Pd-catalyzed enantioselective C-H bond activation reactions. However, to elucidate the mechanistic details and controlling factors these reactions, more comprehensive studies are needed. In this work we report computational investigations into key features reactions catalyzed by [chiral (mono-N-protected acid)-Pd(II)] complex. Structural analysis points insertion intermediate in which...
Described herein are studies toward the core modification of cyclic aliphatic amines using either a riboflavin/photo-irradiation approach or Cu(I) and Ag(I) to mediate process. Structural remodeling is explored through oxidative C–N C–C bond cleavage peroxydisulfate (persulfate) as an oxidant. Ring-opening reactions access linear aldehydes carboxylic acids with flavin-derived photocatalysis Cu salts, respectively, demonstrated. A complementary ring-opening process mediated by facilitates...
Keggin and Dawson-type polyoxometalates (POMs) covalently grafted to heteroleptic cyclometalated iridium(III) complexes (POM–[Ir] dyads) have been prepared by postfunctionalization of organosilyl organotin POM derivatives. Electronic properties these 4 photosensitized POM–[Ir] dyads were evaluated electrochemical measurements theoretical calculations. These studies reveal that the electron acceptor character POMs vary with structural class (Keggin vs. Dawson) chemical anchorage (organosilyl...
Indium phosphide quantum dots (InP QDs) are nontoxic nanomaterials with potential applications in photocatalytic and optoelectronic fields. Post-synthetic treatments of InP QDs known to be essential for improving their photoluminescence efficiencies (PLQEs) device performances, but the mechanisms remain poorly understood. Herein, by applying ultrafast transient absorption spectroscopies, we systematically investigate dynamics photogenerated carriers how they affected two common passivation...
The threat of chemical warfare agents (CWAs), assured by their ease synthesis and effectiveness as a terrorizing weapon, will persist long after the once-tremendous stockpiles in U.S. elsewhere are finally destroyed. As such, soldier civilian protection, battlefield decontamination, environmental remediation from CWAs remain top national security priorities. New approaches for fast complete destruction have been an active field research many decades, new technologies generated immense...
Standard molecular and driven dynamics are used to analyze prominent spectral features in the H5O2+ infrared spectrum. In method, Hamiltonian is augmented with a time-dependent term, μ · ε0 sin(ωt), where dipole moment of H5O2+, electric field, ω frequency. The magnitude field determines whether driving mild (the harmonic limit) or strong (anharmonic motion mode coupling). We spectrum wavenumber range from 600 1900 cm-1, recent experimental measurements available for H5O2+. On basis...
We report the implementation of a previously suggested method to constrain molecular system have mode-specific vibrational energy greater than or equal zero-point in quasiclassical trajectory calculations [J. M. Bowman et al., J. Chem. Phys. 91, 2859 (1989); W. H. Miller 2863 (1989)]. The is made practical by using technique described recently [G. Czako and Bowman, 131, 244302 (2009)], where normal-mode analysis performed during course which gives only real-valued frequencies. applied water...
There has been renewed interest in carbon nanoscale structures. Experimental measurements at 4.7 K and subsequent first-principles-based vibrational diffusion Monte Carlo simulations 0 recently showed that the aromatic cyclo[10]carbon prefers a D5h pentagon-like structure to regular D10h decagon. This symmetry breaking is due second-order Jahn–Teller effect (JTE) amply described literature for cumulenic cyclo[4m + 2]carbon clusters. Yet temperature dependence of JTE clusters general...
An application of the initial value representation (IVR) semiclassical (SC) theory to approximate quantum mechanical time evolution operator, exp[−iĤt/ℏ], requires an integral over phase space conditions classical trajectories. The integrand this is complex, i.e., has a phase, from which coherence (in fact, all quantum) effects arise, but also makes SC-IVR calculations more difficult than ordinary molecular dynamics simulations (the version “sign problem”). A number approaches have been...
A new series of complexes containing two electron donating groups, {M(CO)(3)}(+) ions, M = Re or Mn, on one polytungstate acceptor group have been prepared and characterized. These two-component polyoxometalate (POM) compounds made by reaction solvated ions (M Mn) with [X(2)W(22)O(74)(OH)(2)](12-) (X Sb Bi) POM multidentate ligands in aqueous solution. syntheses reveal that the fac-{WO(OH)(2)}(2+) groups terminal positions these are easily replaced topologically equivalent units...
CsPbI3 perovskite quantum dots (QDs) have shown great potential in light-harvesting and light-emitting applications, which often involve the transfer of charge carriers out these materials. Here, we studied size-dependent separation (CS) recombination (CR) between QDs rhodamine B (RhB) molecules, using transient absorption spectroscopy. When average size decreases from 11.8 nm to 6.5 nm, intrinsic CS time constant 872 ± 52 ps 40.6 4.3 corresponding 3829 51 ns 1384 54 ns. The observed trend...
A method recently developed for calculating vibrational spectral densities of molecules, previously tested successfully on H2O, is applied here to several larger molecules. The relies use a time averaging procedure in the conventional semiclassical (SC) initial value representation (IVR) expression density. convergence SC-IVR average over phase space conditions (of classical trajectories) greatly enhanced by and generally achieved with as few 1000 trajectories per degree freedom....
In this work, we present infrared spectra of H(5)O(2)(+) and its D(5)O(2)(+), D(4)HO(2)(+), DH(4)O(2)(+) isotopologues calculated by classical molecular dynamics simulations on an accurate potential energy surface generated from CCSD(T) calculations, as well the BLYP DFT sampled means Car-Parrinello algorithm. The obtained with internal energies corresponding to a temperature about 30 K are in overall good agreement those experimental measurements quantum dynamical simulations.
We examine the mechanism of electron transfer between [Ru(bpy)3]2+ and [S2O8]2− in aqueous solutions using time-dependent density functional transition charge model levels theory. The calculations support existence a short-lived, optically bright S1 state that decays to lower-lying triplet states T1 T2. leads products, is, [Ru(bpy)3]3+ + SO4−• SO42−. It was shown photoinduced (in 420−520 nm wavelength range) may proceed via both “unimolecular” “bimolecular” pathways, agreement with previous...
Abstract In an effort to develop robust molecular sensitizers for solar fuel production, the electronic structure and photodynamics of transition‐metal‐substituted polyoxometalates (POMs), a novel class compound in this context, was examined. Experimental computational techniques including femtosecond (fs) transient absorption spectroscopy have been used study cobalt‐containing Keggin POMs, [Co II W 12 O 40 ] 6− ( 1 ), III 5− 2 [SiCo (H O)W 11 39 3 4 finding longest lived charge transfer...
Geometry and electronic structure of five species [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](10-) (1), [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](9-) (2), [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](8-) (3), [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](7-) (4), [{Ru(4)O(4)(OH)(2)(H(2)O)(4)}(gamma-SiW(10)O(36))(2)](6-) (5) with different oxidation states Ru centers were studied at the density functional COSMO levels theory. These are expected to be...
Low lying electronic states of the beryllium dimer were investigated by laser induced fluorescence (LIF) and resonance enhanced multiphoton ionization (REMPI) techniques. Be2 was formed pulsed ablation Be metal in presence helium carrier gas, followed a free jet expansion into vacuum. Several previously unobserved characterized. These included transitions triplet manifold (2)3Πg ← (1)3Σ+u (3)3Πg (1)3Σ+u, for which rotationally resolved bands obtained. In addition, to v′ = 10–18 vibrational...
We report a hybrid computational approach to calculate electron transfer between type-I CdSe/ZnS core/shell quantum dot (QD) with varying shell thickness and the functionalized anthraquinone (AQ) molecule. This novel combines traditional electron/hole confinement theory in effective mass approximation for QD molecular orbital AQ In present study, QD's hole envelope wave functions are solutions of effective-mass Schrödinger equation, function is obtained at density functional level....