Purpose. To study the molecular structure of indomethacin-PVP amorphous solid dispersions and identify any specific interactions between the components using vibrational spectroscopy.

Spectroscopic characterization of interactions between PVP and indomethacin in amorphous molecular dispersions.

A compact formalism for the second and third derivatives of the Hartree–Fock energy in the presence of an Onsager solvent reaction field is presented. All three standard algorithms (MO, AO, and direct) are extended to include the reaction field in a unified way. Predictions of the infrared spectrum of formaldehyde in a variety of solvents and of solvent‐induced shifts in carbonyl stretching frequencies are presented along with the results of new measurements. As for the gas‐phase case, analytical second derivatives are far more efficient than numerical ones. The reaction field provides very good predictions of solvent effects at negligible computational cost.

Hartree–Fock second derivatives and electric field properties in a solvent reaction field: Theory and application

The mechanism of the reaction between NOx and NH3 on V2O5 in the presence of oxygen

Theoretical considerations of the molecular hyperpolarizabilities (β) of donor−acceptor substituted aromatic molecules show that the transfer of a proton from the electron-donor group of an acid to the electron acceptor group of a base could increase β for both resulting ionic species relative to the corresponding neutral molecules. To take advantage of this, the cocrystallization of 4-nitrophenol with various organic bases was studied. Cocrystallization of 4-nitrophenol with 4-(dimethylamino)pyridine gives yellow crystals that display a strong second harmonic signal by the Kurtz and Perry powder test. The material crystallizes in the orthorhombic space group P212121 and is composed of 4-(dimethylamino)pyridinium 4-nitrophenolate 4-nitrophenol (DMAPNP2). Theoretical calculations of the hyperpolarizabilities predict that the values of β are greater for the 4-(dimethylamino)pyridinium and 4-nitrophenolate ions than for the corresponding neutral molecules. A second noncentrosymmetric material has been grown ...

L.J. Bellamy

Papers

The use of solvent effects in the identification of carbonyl absorptions in pyridones

The origin of group frequency shifts—I: Abnormal frequencies in multiple bonds

Solvent effects on infra-red group frequencies