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- Chemistry Faculty Publications (4)
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- Chemistry & Biochemistry Faculty Publications (2)
- Chemistry Faculty Research and Publications (2)
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- Biology, Chemistry, and Environmental Sciences Faculty Articles and Research (1)
- Chemistry Faculty Research & Creative Works (1)
- Collected Faculty and Staff Scholarship (1)
- Honors Scholar Theses (1)
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- Research outputs 2022 to 2026 (1)
- Theses and Dissertations (1)
- Turkish Journal of Chemistry (1)
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Articles 1 - 20 of 20
Full-Text Articles in Chemistry
Spectroscopic Study Of The Br−+Ch3i→I−+Ch3br Sn2 Reaction, Hayden T. Robinson, Timothy R. Corkish, Christian T. Haakansson, Peter D. Watson, Allan J. Mckinley, Duncan A. Wild
Spectroscopic Study Of The Br−+Ch3i→I−+Ch3br Sn2 Reaction, Hayden T. Robinson, Timothy R. Corkish, Christian T. Haakansson, Peter D. Watson, Allan J. Mckinley, Duncan A. Wild
Research outputs 2022 to 2026
Mass spectrometry and anion photoelectron spectroscopy have been used to study the gas-phase SN2 reaction involving Br- and CH3I. The anion photoelectron spectra associated with the reaction intermediates of this SN2 reaction are presented. High-level CCSD(T) calculations have been utilised to investigate the reaction intermediates that may form as a result of the SN2 reaction along various different reaction pathways, including back-side attack and front-side attack. In addition, simulated vertical detachment energies of each reaction intermediate have been calculated to rationalise the photoelectron spectra.
Crystal Structure And Vibrational Spectra Of Bis(2-Isobutyrylamidophenyl)Amine:A Redox Noninnocent Ligand, Emrah Aslantatar, Savita K. Sharma, Omar Villanueva, Cora E. Macbeth, İlkay Gümüş, Hakan Arslan
Crystal Structure And Vibrational Spectra Of Bis(2-Isobutyrylamidophenyl)Amine:A Redox Noninnocent Ligand, Emrah Aslantatar, Savita K. Sharma, Omar Villanueva, Cora E. Macbeth, İlkay Gümüş, Hakan Arslan
Turkish Journal of Chemistry
The molecular structure of bis(2-isobutyrylamidophenyl)amine (H3LNNN) has been determined from single-crystal X-ray diffraction data. The crystal packing of H3LNNN is governed by the N-H...O and C-H...O hydrogen-bonding and C-H...π stacking interactions between the vicinal molecules. The intermolecular interactions in the crystal structure of H3LNNN have been also examined via Hirshfeld surface analysis and fingerprint plots. The Hirshfeld surface analysis showed that the important role of N-H...O and C-H...π interactions in the solid-state structure of H3LNNN. The molecular structure, vibrational frequencies, and infrared intensities of H3LNNN were computed by ab initio HF and DFT (B3LYP, B3PW91, and BLYP) methods using the …
Boron-Made N2: Realization Of A B≡B Triple Bond In The B2al3− Cluster, Nikita Fedik, Chaonan Mu, Ivan A. Popov, Wei Wang, Jie Wang, Haopeng Wang, Kit H. Bowen, Alexander I. Boldyrev, Xinxing Zhang
Boron-Made N2: Realization Of A B≡B Triple Bond In The B2al3− Cluster, Nikita Fedik, Chaonan Mu, Ivan A. Popov, Wei Wang, Jie Wang, Haopeng Wang, Kit H. Bowen, Alexander I. Boldyrev, Xinxing Zhang
Chemistry and Biochemistry Faculty Publications
Until now, all B≡B triple bonds have been achieved by adopting two ligands in the L→B≡B←L manner. Herein, we report an alternative route of designing the B≡B bonds based on the assumption that by acquiring two extra electrons, an element with the atomic number Z can have properties similar to those of the element with the atomic number Z+2. Specifically, we show that due to the electron donation from Al to B, the negatively charged B≡B kernel in the B2Al3− cluster mimics a triple N≡N bond. Comprehensive computational searches reveal that the global minimum structure of B2Al3− exhibits a …
Atlas Of Experimental And Theoretical High Temperature Methane Cross Sections From T = 295 To 1000k In The Near-Infrared, Andy Wong, Peter F. Bernath, Michael Rey, Andrei V. Nikitin, Vladimir G. Tyuterev
Atlas Of Experimental And Theoretical High Temperature Methane Cross Sections From T = 295 To 1000k In The Near-Infrared, Andy Wong, Peter F. Bernath, Michael Rey, Andrei V. Nikitin, Vladimir G. Tyuterev
Chemistry & Biochemistry Faculty Publications
Spectra of hot methane were recorded using a tube furnace and a high-resolution Fourier transform spectrometer. We obtained experimental absorption spectra in the 1.85-1.11 μm near-infrared region at eight temperatures ranging from 295 K up to 1000 K. We have converted these into an atlas of absorption cross sections at each temperature for the methane tetradecad, icosad and triacontad polyads, excluding some spectral intervals either strongly contaminated by water or due to baseline fringes. On the theoretical side, the spectra were simulated from the ab initio-based Reims-Tomsk TheoReTS line list for the same experimental conditions. This line list has been …
Vibrational Analysis Of A Rate-Slowing Conformational Kinetic Isotope Effect, O. Maduka Ogba, Zichen Liu, Daniel J. O'Leary
Vibrational Analysis Of A Rate-Slowing Conformational Kinetic Isotope Effect, O. Maduka Ogba, Zichen Liu, Daniel J. O'Leary
Biology, Chemistry, and Environmental Sciences Faculty Articles and Research
An enthalpy-entropy approach to analyzing a rate-slowing conformational kinetic isotope effect (CKIE) in a deuterated doubly-bridged biaryl system is described. The computed isotope effect (kH/kD = 1.075, 368 K) agrees well with the measured value (kH/kD = 1.06, 368 K). The rateslowing (normal isotope effect) nature of the computed CKIE is shown to originate from a vibrational entropy contribution defined by the twenty lowest frequency normal modes in the ground state and transition state structures. This normal entropy contribution is offset by an inverse vibrational enthalpy contribution, which also arises from the twenty lowest frequency normal modes. Zero point vibrational …
Triel-Bonded Complexes Between Trr3 (Tr = B, Al, Ga; R = H, F, Cl, Br, Ch3) And Pyrazine, Mariusz Michalczyk, Wiktor Zierkiewicz, Steve Scheiner
Triel-Bonded Complexes Between Trr3 (Tr = B, Al, Ga; R = H, F, Cl, Br, Ch3) And Pyrazine, Mariusz Michalczyk, Wiktor Zierkiewicz, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Complexes between TrR3 (Tr = B, Al, Ga; R= H, F, Cl, Br, CH3)molecules and pyrazine have been characterized at the MP2 and CCSD(T) levels of theory. The adducts can be grouped according to the type of molecular arrangement. The first situation places the Tr atom in the plane of the pyrazine ring and contains a triel bond to the N lone pair. For the boron complexes the orbital interaction energy is almost equal to the electrostatic component, while the former is only half the latter for Tr= Al and Ga. The two monomers are stacked above one another in …
Molecular Geometries And Other Properties Of H2o⋯Agi And H3n⋯Agi As Characterised By Rotational Spectroscopy And Ab Initio Calculations, Chris Medcraft, Eva Gougoula, Dror M. Bittner, John C. Mullaney, Susana Blanco, David P. Tew, Nicholas R. Walker, Anthony C. Legon
Molecular Geometries And Other Properties Of H2o⋯Agi And H3n⋯Agi As Characterised By Rotational Spectroscopy And Ab Initio Calculations, Chris Medcraft, Eva Gougoula, Dror M. Bittner, John C. Mullaney, Susana Blanco, David P. Tew, Nicholas R. Walker, Anthony C. Legon
Chemistry & Biochemistry Faculty Publications
The rotational spectra of H3N⋯AgI and H2O⋯AgI have been recorded between 6.5 and 18.5 GHz by chirped-pulse Fourier-transform microwave spectroscopy. The complexes were generated through laser vaporisation of a solid target of silver or silver iodide in the presence of an argon gas pulse containing a low concentration of the Lewis base. The gaseous sample subsequently undergoes supersonic expansion which results in cooling of rotational and vibrational motions such that weakly bound complexes can form within the expanding gas jet. Spectroscopic parameters have been determined for eight isotopologues of H3N⋯AgI and six isotopologues of …
An Experimental And Theoretical Study Of Ã2A"Π–X~2A' Band System Of The Jet-Cooled Hbbr/Dbbr Free Radical, Mohammed Gharaibeh, Dennis J. Clouthier, Riccardo Tarroni
An Experimental And Theoretical Study Of Ã2A"Π–X~2A' Band System Of The Jet-Cooled Hbbr/Dbbr Free Radical, Mohammed Gharaibeh, Dennis J. Clouthier, Riccardo Tarroni
Chemistry Faculty Publications
The electronic spectra of the HBBr and DBBr free radicals have been studied in depth. These species were prepared in a pulsed electric discharge jet using a precursor mixture of BBr3 vapor and H2 or D2 in high pressure argon. Transitions to the electronic excited state of the jet-cooled radicals were probed with laser-induced fluorescence and the ground state energy levels were measured from the single vibronic level emission spectra. HBBr has an extensive band system in the red which involves a linear-bent transition between the two Renner-Teller components of what would be a 2Π state …
Sign Learning Kink-Based (Silk) Quantum Monte Carlo For Molecular Systems, Xiaoyao Ma, Randall W. Hall, Frank Loffler, Karol Kowalski, Kiran Bhaskaran-Nair, Mark Jarrell, Juana Moreno
Sign Learning Kink-Based (Silk) Quantum Monte Carlo For Molecular Systems, Xiaoyao Ma, Randall W. Hall, Frank Loffler, Karol Kowalski, Kiran Bhaskaran-Nair, Mark Jarrell, Juana Moreno
Collected Faculty and Staff Scholarship
The Sign Learning Kink (SiLK) based Quantum Monte Carlo (QMC) method is used to calculate the ab initioground state energies for multiple geometries of the H2O, N2, and F2 molecules. The method is based on Feynman’s path integral formulation of quantum mechanics and has two stages. The first stage is called the learning stage and reduces the well-known QMC minus sign problem by optimizing the linear combinations of Slater determinants which are used in the second stage, a conventional QMC simulation. The method is tested using different vector spaces and compared to the results of …
Peroxy Radical - Water Complexes: Their Role In The Atmosphere, Sambhav Rajendra Kumbhani
Peroxy Radical - Water Complexes: Their Role In The Atmosphere, Sambhav Rajendra Kumbhani
Theses and Dissertations
The importance of radical-water complexes in the atmosphere is explored in this dissertation. Radicals, although present in small concentrations in the atmosphere, play a significant role in creating and removing atmospheric pollution. As the atmosphere warms and consequently gets wetter, it is essential to understand the effects of water vapor on radical chemistry. This dissertation reports studies on the effects of water vapor on the kinetics of the self-reaction of β-hydroxyethyl peroxy radical (β-HEP), a prominent organic peroxy radical in the atmosphere. Both experimental and computational studies have been performed to examine the effects of water vapor on the kinetics …
Towards A Global Model Of Spin-Orbit Coupling In The Halocarbenes, Silver Nyambo, Cyrus Karshenas, Scott Reid, Phalgun Lolur, Richard Dawes
Towards A Global Model Of Spin-Orbit Coupling In The Halocarbenes, Silver Nyambo, Cyrus Karshenas, Scott Reid, Phalgun Lolur, Richard Dawes
Chemistry Faculty Research and Publications
We report a global analysis of spin-orbit coupling in the mono-halocarbenes, CH(D)X, where X = Cl, Br, and I. These are model systems for examining carbene singlet-triplet energy gaps and spin-orbit coupling. Over the past decade, rich data sets collected using single vibronic level emission spectroscopy and stimulated emission pumping spectroscopy have yielded much information on the ground vibrational level structure and clearly demonstrated the presence of perturbations involving the low-lying triplet state. To model these interactions globally, we compare two approaches. First, we employ a diabatic treatment of the spin-orbit coupling, where the coupling matrix elements are written in …
Towards A Global Model Of Spin-Orbit Coupling In The Halocarbenes, Silver Nyambo, Cyrus Karshenas, Scott A. Reid, Phalgun Lolur, Richard Dawes
Towards A Global Model Of Spin-Orbit Coupling In The Halocarbenes, Silver Nyambo, Cyrus Karshenas, Scott A. Reid, Phalgun Lolur, Richard Dawes
Chemistry Faculty Research & Creative Works
We report a global analysis of spin-orbit coupling in the mono-halocarbenes, CH(D)X, where X = Cl, Br, and I. These are model systems for examining carbene singlet-triplet energy gaps and spin-orbit coupling. Over the past decade, rich data sets collected using single vibronic level emission spectroscopy and stimulated emission pumping spectroscopy have yielded much information on the ground vibrational level structure and clearly demonstrated the presence of perturbations involving the low-lying triplet state. To model these interactions globally, we compare two approaches. First, we employ a diabatic treatment of the spin-orbit coupling, where the coupling matrix elements are written in …
Bh2 Revisited: New, Extensive Measurements Of Laser-Induced Fluorescence Transitions And Ab Initio Calculations Of Near-Spectroscopic Accuracy, Fumie X. Sunahori, Mohammed Gharaibeh, Dennis J. Clouthier, Riccardo Tarroni
Bh2 Revisited: New, Extensive Measurements Of Laser-Induced Fluorescence Transitions And Ab Initio Calculations Of Near-Spectroscopic Accuracy, Fumie X. Sunahori, Mohammed Gharaibeh, Dennis J. Clouthier, Riccardo Tarroni
Chemistry Faculty Publications
The spectroscopy of gas phase BH2 has not been explored experimentally since the pioneering study of Herzberg and Johns in 1967. In the present work, laser-induced fluorescence (LIF) spectra of the Ã2B1(Πu)-X̃2A1 band system of 11BH2, 10BH2, 11BD2, and 10BD2 have been observed for the first time. The free radicals were "synthesized" by an electric discharge through a precursor mixture of 0.5% diborane (B2H6 or B2D6) in high pressure argon at the exit of …
Applied Quantum Chemistry: Spectroscopic Detection And Characterization Of The F2Bs And Cl2Bs Free Radicals In The Gas Phase, Bing Jin, Phillip M. Sheridan, Dennis J. Clouthier
Applied Quantum Chemistry: Spectroscopic Detection And Characterization Of The F2Bs And Cl2Bs Free Radicals In The Gas Phase, Bing Jin, Phillip M. Sheridan, Dennis J. Clouthier
Chemistry Faculty Publications
In this and previous work [D. J. Clouthier, J. Chem. Phys. 141, 244309 (2014)], the spectroscopic signatures of the X2BY (X = H, halogen, Y = O, S) free radicals have been predicted using high level ab initio theory. The theoretical results have been used to calculate the electronic absorption and single vibronic level (SVL) emission spectra of the radicals under typical jet-cooled conditions. Using these diagnostic predictions, the previously unknown F2BS and Cl2BS free radicals have been identified and characterized. The radicals were prepared in a free jet expansion by subjecting precursor …
In Search Of The X2Bo And X2Bs (X = H, F) Free Radicals: Ab Initio Studies Of Their Spectroscopic Signatures, Dennis J. Clouthier
In Search Of The X2Bo And X2Bs (X = H, F) Free Radicals: Ab Initio Studies Of Their Spectroscopic Signatures, Dennis J. Clouthier
Chemistry Faculty Publications
The F2BO free radical is a known, although little studied, species but similar X2BY (X = H, D, F; Y = O, S) molecules are largely unknown. High level ab initio methods have been used to predict the molecular structures, vibrational frequencies (in cm-1), and relative energies of the ground and first two excited electronic states of these free radicals, as an aid to their eventual spectroscopic identification. The chosen theoretical methods and basis sets were tested on F2BO and found to give good agreement with the known experimental quantities. In particular, …
Global Permutationally Invariant Potential Energy Surface For Ozone Forming Reaction, Mehdi Ayouz, Dmitri Babikov
Global Permutationally Invariant Potential Energy Surface For Ozone Forming Reaction, Mehdi Ayouz, Dmitri Babikov
Chemistry Faculty Research and Publications
We constructed new global potential energy surface for O + O2 → O3 reaction. It is based on high level electronic structure theory calculations and employs fitting by permutationally invariant polynomial functions. This method of surface construction takes full advantage of permutation symmetry of three O nuclei and allows reducing dramatically the number of ab initio data points needed for accurate surface representation. New potential energy surface offers dramatic improvement over older surface of ozone in terms of dissociation energy and behavior along the minimum energy path. It can be used to refine the existing theories of ozone …
Contributions Of Various Noncovalent Bonds To The Interaction Between An Amide And S-Containing Molecules, U. Adhikari, Steve Scheiner
Contributions Of Various Noncovalent Bonds To The Interaction Between An Amide And S-Containing Molecules, U. Adhikari, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
N-Methylacetamide, a model of the peptide unit in proteins, is allowed to interact with CH3SH, CH3SCH3, and CH3SSCH3 as models of S-containing amino acid residues. All of the minima are located on the ab initio potential energy surface of each heterodimer. Analysis of the forces holding each complex together identifies a variety of different attractive forces, including SH⋅⋅⋅O, NH⋅⋅⋅S, CH⋅⋅⋅O, CH⋅⋅⋅S, SH⋅⋅⋅π, and CH⋅⋅⋅π H-bonds. Other contributing noncovalent bonds involve charge transfer into σ* and π* antibonds. Whereas some of the H-bonds are strong enough that they represent the sole attractive force in several dimers, albeit not usually in the …
Microwave Spectroscopy And Structures Of Several Substituted Acetylenes And Fluorocarbons, Joseph A. Fournier
Microwave Spectroscopy And Structures Of Several Substituted Acetylenes And Fluorocarbons, Joseph A. Fournier
Honors Scholar Theses
The structures of two substituted acetylene compounds have been characterized from their microwave rotational spectra. In the first study, two structures of 6-methyl-3-heptyne have been determined. This compound can be thought of as an ethyl group separated from an isobutyl group by a C≡C spacer. Both structures have the ethyl and isobutyl groups eclipsed, consistent with the dominant interaction determining the orientation about the acetylene axis being the weak dispersion attraction between the end groups. One structure is with the isobutyl group in a symmetric conformation and the other with the isobutyl group asymmetric. In addition, the microwave spectrum of …
The Initial And Final States Of Electron And Energy Transfer Processes: Diabatization As Motivated By System-Solvent Interactions, Joseph E. Subotnik, Robert J. Cave, Ryan P. Steele, Neil Shenvi
The Initial And Final States Of Electron And Energy Transfer Processes: Diabatization As Motivated By System-Solvent Interactions, Joseph E. Subotnik, Robert J. Cave, Ryan P. Steele, Neil Shenvi
All HMC Faculty Publications and Research
For a system which undergoes electron or energy transfer in a polar solvent, we define the diabatic states to be the initial and final states of the system, before and after the nonequilibrium transfer process. We consider two models for the system-solvent interactions: A solvent which is linearly polarized in space and a solvent which responds linearly to the system. From these models, we derive two new schemes for obtaining diabatic states from ab initio calculations of the isolated system in the absence of solvent. These algorithms resemble standard approaches for orbital localization, namely, the Boys and Edmiston–Ruedenberg (ER) formalisms. …
Effect Of Surrounding Point Charges On The Density Functional Calculations Of NiXOX Clusters (X = 4–12), Evgueni B. Kadossov, Karen J. Gaskell, Marjorie Langell
Effect Of Surrounding Point Charges On The Density Functional Calculations Of NiXOX Clusters (X = 4–12), Evgueni B. Kadossov, Karen J. Gaskell, Marjorie Langell
Marjorie A. Langell Publications
Embedded NixOx clusters (x = 4–12) have been studied by the density-functional method using compensating point charges of variable magnitude to calculate the ionic charge, bulk modulus, and lattice binding energy. The computations were found to be strongly dependent on the value of the surrounding point charge array and an optimum value could be found by choosing the point charge to reproduce the experimentally observed Ni–O lattice parameter. This simple, empirical method yields a good match between computed and experimental data, and even small variation from the optimum point charge value produces significant deviation between computed …