The computational algorithm that works in the coordinate space of dihedral angles (i.e., bond lengths and bond angles are kept fixed and only rotatable dihedral angles are treated as independent variables) is extended to deal with the pseudorotational motion of furanose rings by introducing a variable of pseudorotation. Then, this algorithm is applied to a distance geometry calculation that gen...

The title compound, [CuCl(2)(C(21)H(19)N(3))], lies on a twofold rotation axis that passes through the N(pyrid-yl)-Cu bond; this symmetry element relates one half of the organic ligand to the other as well as one Cl ligand to the other. The three N atoms span the axial-equatorial-axial sites of the trigonal-bipyramidal coordination polyhedron; the geometry of the Cu(II) atom is 31% distorted fr...

We report the first observation of five water trimer isotopomers using terahertz laser spectroscopy coupled with a pulsed slit jet expansion technique. A single c-type vibration-rotation-tunneling (VRT) band has been observed for each isotopomer between 40 and 50 cm-1. By considering all the experimental data, including results from isotopic substitution experiments, analyses of bifurcation tun...

A method is presented whereby the WKB expression for tunneling frequencies permits correlation of the.se frequencies for members of homologous series of molecules. The necessary data required are the tunneling rate for one member of the series, and structural parameters and vibrational frequencies for all members of interest. The method is applied to NDz, NF" PH" and AsH" using NH. as the molec...

The temperature dependence of the nmr spectra of (CH&NPF4 (l), ClPF4, and CH3PF4 has been examined. The interchange of axial and equatorial fluorines in (CH&NPF4 and ClPF, follows the permutational scheme expected for Berry pseudorotation; uiz., both axial and equatorial fluorine atoms interchange at the same time. The rate of pseudorotation of 1 is independent of the concentration of 1 but is ...

Hexa(4-n-dodecylbiphenylyl)benzene (HDBB) was reduced by a series of alkali metals in THF under high vacuum. Three reduction states were identified by NMR spectroscopy, namely the dianion, tetraanion and hexaanion. The NMR spectra of HDBB(6-) revealed a remarkable distortion of symmetry, which is interpreted by adoption of a twisted conformation of the central benzene ring and a slow rotation o...

Density functional ~DF! calculations have been performed for lithium clusters Lin and their monoxides LinO with up to ten atoms. There are numerous stable structures, and new isomers have been found in each family. The structural patterns of the homonuclear and oxide clusters are quite distinct. The combination of DF calculations with molecular dynamics ~MD! sheds light on the observed pseudoro...

A relatively simple treatment using perturbation theory is proposed to describe spectrum of pseudorotational states in cyclic-N(3). The purpose is to develop an analytical expression that could be used to fit the experimentally determined spectrum of cyclic-N(3), with purpose of identifying this molecule in the laboratory and deriving parameters of its potential energy surface directly from the...