This paper deals with the study of two types of hydrogen bonding: a quasi-aromatic hydrogen bonding in dipyrromethene and the ionic one in dipyrromethane. The study focuses on two phenomena-the proton transfer process and tautomeric equilibrium. Metric parameters and spectroscopic assignments have been calculated; this allowed a further comparison of spectral features calculated with four metho...

Chiral recognition has been studied in neutral or ionic weakly bound complexes isolated in the gas phase by combining laser spectroscopy and quantum chemical calculations. Neutral complexes of the two enantiomers of lactic ester derivatives with chiral chromophores have been formed in a supersonic expansion. Their structure has been elucidated by means of IR-UV double resonance spectroscopy in ...

for an Invited Paper for the MAR08 Meeting of The American Physical Society Dangling-bond defects and hydrogen passivation in germanium JUSTIN R. WEBER, Department of Physics, University of California, Santa Barbara, California 93106-9530, USA The application of germanium in complementary metal-oxide semiconductor (CMOS) technology is hampered by high interface-state densities, the microscopic ...

Hydrogen bonds profoundly influence the architecture and activity of biological macromolecules. Deep appreciation of hydrogen bond contributions to biomolecular function thus requires a detailed understanding of hydrogen bond structure and energetics and the relationship between these properties. Hydrogen bond formation energies (ΔGf) are enormously more favorable in aprotic solvents than in wa...

Quantification of backbone hydrogen bond energies in protein folding has remained elusive despite extensive theoretical and experimental investigations over the past 70 years. This is due to difficulties in experimental mutagenesis study as well as the lack of quantitatively reliable methods in theoretical calculation. Recent advance in experiment has enabled accurate measurement of site-specif...

The title compound, C(14)H(11)BrN(2)O(5)·2H(2)O, crystallizes as hydrogen-bonded sheets. The 2-hydr-oxy group on the benzyl-idene group forms an intra-molecular hydrogen bond to the N atom of the C=N double bond. The amino N atom is a hydrogen-bond donor to a water mol-ecule. The hydr-oxy group on the benzohydrazide group is a hydrogen-bond donor to one acceptor site, whereas each water mol-ecu...

Ultrafast infrared transient absorption measurements of the complete hydroxyl OD stretching mode spectrum of HOD in water, from 100 fs to tens of picoseconds, observe hydrogen bond breaking and monitor the equilibration of the hydrogen bond network in water. In addition, the vibrational lifetime, the time constant for hydrogen bond breaking, and the rate of orientational relaxation are determin...

The adsorption of glycine on amorphous silica surface has been studied to demonstrate the catalytic activity surfaces towards formation peptide bonds prebiotic earth. Silica nanoparticles were synthesized using a microwave assisted method and characterized SEM. Glycine was adsorbed from aqueous solution behavior FTIR TGA analyses. At concentration 0.5M at pH=7, favorable observed which obeyed L...

In a previous paper,' a model of the hydrogen bond was proposed that gave a structure for water differing markedly from others that have been suggested.2 According to this model, the hydrogen bond would not be located between any two atoms of a given molecular system, as in the case of an ordinary bond, but it would be a collective bond linking a number of molecules together and consisting of a...