Showing papers in "Journal of Molecular Structure in 1986"

TL;DR: In this paper, a compilation of spectroscopic and structural data of solid hydrates 61 different compounds containing more than 250 O�D(H)⋯Y groups have been selected, for which uncoupled OD stretching frequencies, hydrogen bond distances and assignments of sufficient reliability and accuracy are available.

TL;DR: In this article, the ground state structures of disilane and silyl halides were determined from the isolated SiH stretching frequency, at least for molecules with fully saturated bonding.

TL;DR: In this article, the Raman spectra of chlorophyll a (Chl) forms in aqueous polyvinyl alcohol (PVA) and in dimethyl sulfoxide (DMSO) water mixtures were recorded at 457.9 nm excitation and their structures were characterized by comparison with the Spectra of the following well-known Chl forms: (1) monomers (ChL) 1 in the polar solvents of group (A), i.e., diethyl ether, tetrahydrofuran, acetone, N

TL;DR: In this article, a nearly complete set of assignments of all the observed Raman lines in the 1700-150 cm−1 range is proposed on the basis of a previous normal coordinate treatment of guanine and cytosine with a set of force constants determined by an ab initio MO method, and based on a mutual comparison of the observed spectra.

TL;DR: In this paper, the microwave spectrum of the normal isotopic species of anisole was observed in the frequency ranges 8-18 and 26.5-40 GHz, and the ground vibrational state and the excited states of the torsional vibration of the phenyl group were obtained.

TL;DR: In this paper, the room temperature crystal structures of three hydroxy-flavone derivatives have been solved, and the relationships between molecular conformation and solid-state aggregate patterns of 3-hydroxyflavones and related molecules are discussed in terms of possible ground state solute solute-solvent and solvent-solute solution structures.

TL;DR: In this paper, the SERS spectra of denatured and thermally denaturated DNA adsorbed on silver sol in concentration ranges of the order 10 μg ml −1 are reported.

TL;DR: In this article, the molecular structure of free uracil has been determined by electron diffraction and the following bond lengths (rg and bond angles (rα) were determined; the estimated total errors are parenthesized as expressed in units of the last digit.

TL;DR: In this article, the interpretation of the infrared intensities in terms of atomic polar tensors and of electrooptical parameters allows to derive rich information on the charge distribution in the molecules, and it is possible to derive information on intramolecular and intermolecular interactions even from poor data such as absolute intensities of whole regions in the spectrum or even from relative intensities.

TL;DR: In this paper, the far infrared spectrum of ehtylphosphine was measured at 1 2 cm −1 nominal resolution, which was used together with splitting data from microwave spectroscopy to determine a new potential function for the asymmetric internal rotation.

TL;DR: In this article, a molecular mechanics force field for conformational and vibrational studies on acyl chlorides, carboxylic acids and esters has been developed, which can also be applied to alkanes, alcohols and ethers.

TL;DR: In this article, the normal modes of toluene, a typical monosubstituted benzene, were compared with the normal mode of benzene itself, and new notations for the normalized modes of benzenes were proposed.

TL;DR: The effect of temperature, pH and addition of denaturing agents on the amide and side chain NH δ values of a series of random coil linear tetrapeptides has been measured in dilute aqueous solutions at two temperatures (24 and 0°C) as discussed by the authors.

TL;DR: In this article, the structure of methyl acetate was studied by joint analysis of gas phase electron diffraction, microwave and IR data, using constraints taken from relaxed 4-21G gradient geometry and force field calculations.

TL;DR: In this paper, the third-order anharmonic potential constants for the stretching modes were derived in terms of the diatomic-molecule model, and equilibrium structure parameters for the formyl and hydroperoxyl radicals were derived.

TL;DR: In this paper, a constrained valence force field for trans glycolic acid based on certain transferability rules is reported for eight conformers with a planar skeleton and for some non-planar conformations possibly involved in the reaction path.

TL;DR: The geometrical parameters for the two conformers, gauche ( g ) and trans ( t ), of ethylamine have been determined by a joint analysis of the electron diffraction intensity measured in the present study and the rotational constants reported in the literature as mentioned in this paper.

TL;DR: The contribution of the CH bond to the total intensity in the CH stretching region (Astr) and the CH deformation region (Adef) can be easily measured for several compounds.

TL;DR: In this article, normal coordinate calculations are presented for the D 3d − and C i -symmetric structures of 18-crown-6, 15-c crown-5, and their complexes with Li +, Na +, K +, Cs +, Mg 2+, Ca 2+ and Ba 2+ have been investigated in methanol solution.

TL;DR: A number of organic monoazides have been synthesized in which R is: (1) a saturated group, CH 3, C 2 H 5, nC 3 H 7 ; (2) an olefinic group, allyl, butadiene; (3) an acetylenic group, N

TL;DR: In this paper, the gas phase molecular structure of s-triazine has been determined from electron diffraction data, and the vibrational parameters proved consistent with those from the 4-21G force field after scaling onto infrared/Raman frequencies, as well as after direct scaling.

TL;DR: In this paper, the IR intensity and the harmonic force constant of the NH stretch mode in peptide NH⋯OC hydrogen bonds are studied as functions of the hydrogen-bond geometry using a model complex of N-methylacetamide and formamide.

TL;DR: In this article, the molecular structure of CF 3 SiH 3 in the gas phase has been determined by electron diffraction analysis and force constants have been calculated by means of a normal coordinate analysis based on 52 experimental frequencies.

TL;DR: In this paper, the authors assessed the conformational effects in CHCl 2 COX and CCl 3 COX (X = Cl, OH, OCH 3 ) by molecular mechanics and vibrational spectroscopy.

TL;DR: In this article, the deuterated derivatives of Ni(II) [Ni(PP)] were observed in CH2Cl2, CCl4 and benzene solutions using 406.7, 441.6 and 514.5 nm excitation lines.

TL;DR: The surface enhaced Raman scattering of pyrazine in a silver sol was investigated in this article, where strong enhancement of the g modes and appearance of forbidden vibrations were observed, in agreement with existing results obtained on electrode surface.

TL;DR: In this paper, the microwave spectra of 4-fluorophenol, 4-chlorophenol and 4-bromophenol are analyzed in the frequency region 18-40 GHz.

TL;DR: A survey of 832 hydrogen bonds in 45 crystal structures of barbiturates and 214 crystal structure of purines and pyrimidines showed well-defined distributions of hydrogen-bond length characteristics of the donor/acceptor combinations as mentioned in this paper.

TL;DR: In this article, a combination of molecular mechanics and vibrational spectroscopy was used to study the structure and properties of liquid CClH 2 COOCH 3 and its conformer energy differences and barriers to internal rotation.