Harmonic vibrational frequencies: scale factors for pure, hybrid, hybrid meta, and double-hybrid functionals in conjunction with correlation consistent basis sets.

Scale factors for (a) low (<1000 cm(-1)) and high harmonic vibrational frequencies, (b) thermal contributions to enthalpy and entropy, and (c) zero-point vibrational energies have been determined for five hybrid functionals (B3P86, B3PW91, PBE1PBE, BH&HLYP, MPW1K), five pure functionals (BLYP, BPW91, PBEPBE, HCTH93, and BP86), four hybrid meta functionals (M05, M05-2X, M06, and M06-2X) and one double-hybrid functional (B2GP-PLYP) in combination with the correlation consistent basis sets [cc-pVnZ and aug-cc-pVnZ, n = D(2),T(3),Q(4)]. Calculations for vibrational frequencies were carried out on 41 organic molecules and an additional set of 22 small molecules was used for the zero-point vibrational energy scale factors. Before scaling, approximately 25% of the calculated frequencies were within 3% of experimental frequencies.

Vibrational spectroscopy of secondary amine salts: 1. Assignment of NH(2)(+) stretching frequencies in crystalline phases.

The NH(2)(+) stretching modes of secondary amine salts have been previously studied, but the band assignments are inconsistent between the various studies. This paper assigns characteristic NH(2)(+) group frequencies between approximately 2500 and 2400 cm(-1). Crystal structures of four diamine salts are reported here.

The vibrational spectrum of the secondary electron acceptor, A1, in photosystem I.

Photosystem I (PSI) is a multisubunit protein complex which carries out light-induced, transmembrane charge separation in oxygenic photosynthesis. In PSI, the electron-transfer pathway consists of chlorophyll and phylloquinone molecules, as well as iron-sulfur clusters. There are two phylloquinone molecules, which are located in structurally symmetric positions in the reaction center.