0000000000014658
AUTHOR
S. Abbate
Molecular dynamics of electrosprayed water nanodroplets containing sodium bis(2-ethylhexyl)sulfosuccinate
The behavior of aqueous solutions of sodium bis(2-ethylhexyl)sulfosuccinate (AOTNa) subject to electrospray ionization (ESI) has been investigated by molecular dynamics (MD) simulations at three temperatures (350, 500 and 800 K). We consider several types of water nanodroplets containing AOTNa molecules and composed of a fixed number of water molecules (1000), N(AOT)(0) AOT(-) anions (N(AOT)(0) = 0, 5, 10) and N(Na)(0) sodium ions (N(Na)(0) = 0, 5, 10, 15, 20): in a short time scale (less than 1 ns), the AOTNa molecules, initially forming direct micelles in the interior of the water nanodroplets, are observed in all cases to diffuse nearby the nanodroplet surface, so that the hydrophilic …
Characterisation of the glycosidic linkage by infrared and Raman spectroscopy in the C-H stretching region: α,α-trehalose and α,α-trehalose-2,3,4,6,6-d10
Abstract I.r. and Raman spectra of solid α,α-trehalose and α,α-trehalose- 2,3,4,6,6-d 10 in the C-H and C-D stretching regions are recorded. The experimental data are reproduced satisfactorily by normal co-ordinate and i.r. absorption intensity calculations which take into account the specific interactions of each C-H hydrogen with nearby oxygen lone-pairs. The relevance of the region 2800–3000 cm −1 in α,α-trehalose- 2,3,4,6,6-d 10 for the study of the conformational properties of the inter-glycosidic linkage is discussed.
Evaluation of the Strength of Coupling Between a Vibrational Exciton and a Specific Low Frequency Mode
In Davydov’s theory, one dimensional sub-systems within molecular crystals may exhibit self-trapping of some high frequency phonons as these travel by dipole resonance interaction, due to coupling to some specific soft oscillation mode1
Analysis of the transition from normal modes to local modes in a system of two harmonically coupled Morse oscillators
The system consisting of two Morse oscillators coupled via either a potential or a kinetic quadratic term is considered. The corresponding classical equations of motion have been numerically integrated and the initial conditions have been systematically analyzed in the regime of low total excitation energy of the system. Particular attention was paid to the full characterization of an intermediate type of motion, herein called transition mode, which appears at total energy values in between those typical of normal modes and those where local and normal modes coexist. A previously proposed perturbative approach (Jaffe C, Brumer P (1980) J Chem Phys 73:5646) is reanalyzed and compared with th…
HIGHLY EXCITED VIBRATIONAL STATES OF CYCLIC MOLECULES INVESTIGATED BY I.C.L.A SPECTROSCOPY WITH PHOTOACOUSTIC DETECTION
The spectra of the fourth and fifth CH stretching overtones of cyclohexene and cyclopentene molecules and of some of their selectively deuterated derivatives have been measured by dye laser intracavity spectroscopy with photoacoustic detection. The intramolecular relaxation of the vibrational energy occurs principally through Fermi resonances with CH2 bending combinations in cyclohexene and through a coupling between the stretching and the ring puckering motions in cyclopentene.
Study of Confined 5-Aza[5]helicene in Ytterbium(III) Bis(2-ethylhexyl) Sulfosuccinate Reversed Micelles
Some relevant physicochemical properties of 5-aza[5]helicene (H5) in solutions of ytterbium bis(2-ethylhexyl) sulfosuccinate (Yb(DEHSS)3) reversed micelles have been investigated by UV-vis-NIR, photoluminescence, and FT-IR techniques with the aim of emphasizing the role played by specific Yb(III)/H5 interactions and confinement effects as driving forces of its binding to reversed micelles, preferential solubilization site, and local photophysical properties. It has been found that the binding strength of 5-aza[5]helicene to reversed micelles, triggered by steric and orientational constrains as well as the water content, is mainly regulated by its interaction with the Yb(III) counterion. Mor…