Physical Sciences and Mathematics Commons^™

Modeling The Alkaline Hydrolysis Of Diaryl Sulfate Diesters: A Mechanistic Study, Klaudia Szeler, Nicholas H. Williams, Alvan C. Hengge, Shina C. Kamerlin

Chemistry and Biochemistry Faculty Publications

Phosphate and sulfate esters have important roles in regulating cellular processes. However, while there has been substantial experimental and computational investigation of the mechanisms and the transition states involved in phosphate ester hydrolysis, there is far less work on sulfate ester hydrolysis. Here, we report a detailed computational study of the alkaline hydrolysis of diaryl sulfate diesters, using different DFT functionals as well as mixed implicit/explicit solvation with varying numbers of explicit water molecules. We consider the impact of the computational model on computed linear free-energy relationships (LFER) and the nature of the transition states (TS) involved. We obtain good …

Molecular Rotation In 3 Dimensions At An Air/Water Interface Using Femtosecond Time Resolved Sum Frequency Generation, Yi Rao, Yuqin Qian, Gang-Hua Deng, Ashlie Kinross, Nicholas J. Turro, Kenneth B. Eisenthal

Chemistry and Biochemistry Faculty Publications

This paper presents the first study of the rotations of rigid molecules in 3 dimensions at the air/water interface, using the femtosecond time resolved sum frequency generation (SFG) technique. For the purpose of this research, the aromatic dye molecule C153 was chosen as an example of a molecule having two functional groups that are SFG active, one being the hydrophilic −−C==O group and the other the hydrophobic −−CF₃ group. From polarized SFG measurements, the orientations of the two chromophores with respect to the surface normal were obtained. On combining these results with the known relative orientation of the two …

Proton‐Donor Properties Of Water And Ammonia In Van Der Waals Complexes. Be–H2o And Be–Nh3, G. Chalasinski, M. M. Szczesniak, Steve Scheiner

Steve Scheiner

The potential energy surfaces (PES) of Be–H₂O and Be–NH₃ are studied with particular attention to characterization of proton‐donor properties of water and ammonia. Calculations were performed by means of both supermolecular and intermolecular Møller Plesset perturbation theory. The Be–H₂O PES reveals two van der Waals minima: the C_2v minimum (D_e=176 cm⁻¹, R_e=6.5 bohr), and the H‐bonded minimum (D_e=161 cm⁻¹, R_e=7.5 bohr), separated by a barrier of 43 cm⁻¹ at the T‐shaped configuration. The Be–NH₃ PES reveals only …

Proton‐Donor Properties Of Water And Ammonia In Van Der Waals Complexes. Be–H2o And Be–Nh3, G. Chalasinski, M. M. Szczesniak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The potential energy surfaces (PES) of Be–H₂O and Be–NH₃ are studied with particular attention to characterization of proton‐donor properties of water and ammonia. Calculations were performed by means of both supermolecular and intermolecular Møller Plesset perturbation theory. The Be–H₂O PES reveals two van der Waals minima: the C_2v minimum (D_e=176 cm⁻¹, R_e=6.5 bohr), and the H‐bonded minimum (D_e=161 cm⁻¹, R_e=7.5 bohr), separated by a barrier of 43 cm⁻¹ at the T‐shaped configuration. The Be–NH₃ PES reveals only …

Proton–Donor Properties Of Water And Ammonia In Van Der Waals Complexes With Rare‐Gas Atoms. Kr–H2o And Kr–Nh3, G. Chalasinski, M. M. Szczesniak, Steve Scheiner

Steve Scheiner

The perturbation theory of intermolecular forces in conjunction with the supermolecular Møller–Plesset perturbation theory is applied to the analysis of the potential‐energy surfaces of Kr–H₂O and Kr–NH₃ complexes. The valleylike minimum region on the potential‐energy surface of Kr–H₂O ranges from the coplanar geometry with the C₂ axis of H₂O nearly perpendicular to the O–Kr axis (T structure) to the H‐bond structure in which Kr faces the H atom of H₂O. Compared to the previously studied Ar–H₂O [J. Chem. Phys. 94, 2807 (1991)] the minimum has more …

Proton–Donor Properties Of Water And Ammonia In Van Der Waals Complexes With Rare‐Gas Atoms. Kr–H2o And Kr–Nh3, G. Chalasinski, M. M. Szczesniak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

The perturbation theory of intermolecular forces in conjunction with the supermolecular Møller–Plesset perturbation theory is applied to the analysis of the potential‐energy surfaces of Kr–H₂O and Kr–NH₃ complexes. The valleylike minimum region on the potential‐energy surface of Kr–H₂O ranges from the coplanar geometry with the C₂ axis of H₂O nearly perpendicular to the O–Kr axis (T structure) to the H‐bond structure in which Kr faces the H atom of H₂O. Compared to the previously studied Ar–H₂O [J. Chem. Phys. 94, 2807 (1991)] the minimum has more …

Correction Of The Basis Set Superposition Error In Scf And Mp2 Interaction Energies. The Water Dimer, M. M. Szczesniak, Steve Scheiner

Chemistry and Biochemistry Faculty Publications

There has been some discussion concerning whether basis set superposition error is more correctly evaluated using the full set of ghost orbitals of the partner molecule or some subset thereof. A formal treatment is presented, arguing that the full set is required at the Møller–Plesset level. Numerical support for this position is provided by calculation of the interaction energy between a pair of water molecules, using a series of moderate sized basis sets ranging from 6‐31G∗∗ to the [432/21] contraction suggested by Clementi and Habitz. These energies, at both the SCF and MP2 levels, behave erratically with respect to changes …

Calcium Carbonate Dissolution And Precipitation In Water: Factors Affecting The Carbonate Saturometer Method, Lyle M. Dabb

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

The carbonate saturometer method developed by Weyl (1961) was studied in respect to the effect of several variables on the solubility of carbonates. The solubility of three solid carbonate materials was measured in four different salt solutions, at four ionic strengths, and at two different temperatures. The solids studied included: calcite, dolomite, and a calcareous soil.

It was found that the three solid carbonate materials varied in solubility from a low in the soil carbonates to a high in dolomite.

Increasing the ionic strength of the solution increased the solubility of most of the solid carbonate materials.

By decreasing the …