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Full-Text Articles in Physical Sciences and Mathematics
Proton‐Donor Properties Of Water And Ammonia In Van Der Waals Complexes. Be–H2o And Be–Nh3, G. Chalasinski, M. M. Szczesniak, Steve Scheiner
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 C2v minimum (De=176 cm−1, Re=6.5 bohr), and the H‐bonded minimum (De=161 cm−1, Re=7.5 bohr), separated by a barrier of 43 cm−1 at the T‐shaped configuration. The Be–NH3 PES reveals only …
Theoretical Vibrational Study Of Fx...Nh3 (X=H, D, Li) Complexes, Y. Bouteiller, Z. Latajka, H. Ratajczak, Steve Scheiner
Theoretical Vibrational Study Of Fx...Nh3 (X=H, D, Li) Complexes, Y. Bouteiller, Z. Latajka, H. Ratajczak, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
This paper presents the first ab initio attempt to construct the stretching fundamentals νFX and νF...N (X=H, D, Li) in the FX...NH3 complexes taking into account the mechanical anharmonicity. A potential‐energy surface V(rFX,RF...N) grid was generated at the self‐consistent‐field and second‐order Møller–Plesset levels. The coefficients fitting the potential‐energy surface up to the fourth order have been used to compute the νFX and νF...N stretching modes. The vibrational problem is solved by means of a variational treatment which includes the effects of mechanical …
Vibrational Frequencies And Intensities Of H‐Bonded And Li‐Bonded Complexes. H3n⋅⋅Hcl And H3n⋅⋅Licl, M. M. Szczesniak, I. J. Kurnig, Steve Scheiner
Vibrational Frequencies And Intensities Of H‐Bonded And Li‐Bonded Complexes. H3n⋅⋅Hcl And H3n⋅⋅Licl, M. M. Szczesniak, I. J. Kurnig, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
The geometries, energetics, and vibrational spectra are calculated for the two complexes at the SCF and correlated MP2 levels using the 6‐31G∗∗ basis set, augmented by a second set of d functions on Cl. While correlation represents an important factor in the binding of H3 N⋅⋅HCl, it contributes little to the stronger Li bond. Unlike the HCl stretch νs which decreases substantially in frequency and is greatly intensified in H3 N⋅⋅HCl, the frequency of the LiCl stretch undergoes an increase and little change is noted in its intensity, conforming to prior spectral measurements. The intensities of the …
Vibrational Frequencies And Intensities Of H-Bonded Systems. 1:1 And 1:2 Complexes Of Nh3 And Ph3 With Hfvibrational Frequencies And Intensities Of H‐Bonded Systems. 1:1 And 1:2 Complexes Of Nh3 And Ph3 With Hf, I. J. Kurnig, M. M. Szczesniak, Steve Scheiner
Vibrational Frequencies And Intensities Of H-Bonded Systems. 1:1 And 1:2 Complexes Of Nh3 And Ph3 With Hfvibrational Frequencies And Intensities Of H‐Bonded Systems. 1:1 And 1:2 Complexes Of Nh3 And Ph3 With Hf, I. J. Kurnig, M. M. Szczesniak, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Frequencies and intensities are calculated by ab initio methods for all vibrational modes of the 1:1 H3X–HF and 1:2 H3X–HF–HF complexes (X=N,P). The HF stretching frequencies are subject to red shifts, roughly proportional to the strength of the H bond, and to manyfold increases in intensity. Although the intramolecular frequency shifts within the proton acceptors are relatively modest, the intensities of the NH3 stretches are magnified by several orders of magnitude as a result of H bonding (in contrast to PH3 which exhibits little sensitivity in this regard). …
Ab Initio Comparison Of H Bonds And Li Bonds. Complexes Of Lif, Licl, Hf, And Hcl With Nh3, Z. Latajka, Steve Scheiner
Ab Initio Comparison Of H Bonds And Li Bonds. Complexes Of Lif, Licl, Hf, And Hcl With Nh3, Z. Latajka, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Ab initio calculations are carried out on the complexes H3N–LiF, H3N–LiCl and their analogs H3N–HF and H3N–HCl as well as the isolated subunits. Double‐zeta basis sets, augmented by two sets of polarization functions, are used in conjunction with second‐order Moller–Plesset perturbation theory (MP2) for evaluation of electron correlation effects. The Li bonds are found to be substantially stronger than their H‐bonding counterparts, due in large measure to the greater dipole moments of the LiX subunits. Correlation has a large effect on the geometry and energetics of …