Very short hydrogen bonds universally show large positive dependences of the deuterium NMR quadrupolar coupling constant with temperature. We present temperature dependent NMR data for eight such systems, with O/O distances of between 238 and 250 pm, and show we can model the temperature dependences by density functional methods, as long as proper attention is paid to intermolecular effects and...

density functional theory (dft) calculations have been performed to investigating the effects of themolecular oxygen impurity on the quadrupole coupling constant (qcc) parameters of armchair and zigzagboron nitride nanotubes (bnnts). optimization processes have been performed to relax the original andimpure structures of the investigated bnnts. afterwards, the qcc parameters have been evaluated...

The nuclear quadrupole resonance of 14N was observed in KoPt(SCN)6 and K2Hg(SCN)4 at various temperatures. Both compounds yield large asymmetry parameters indicating the existence of asymmetric ^-electron distribution about a CN bond axis. The ionic character of metal-ligand bonds in the platinum and mercury complexes is estimated to be 28% and 58 %, respectively. The temperature dependence of ...

The power spectra of the scalarand tensor-type structures generated in an inflation model based on nonminimally coupled scalar field are derived. The contributions of these structures to the anisotropy of the cosmic microwave background radiation are derived, and are compared with the four year COBE DMR data. The constraints on the ratio of the self-coupling and nonmimimal coupling constants, t...

NMR signals of 7Li, 23Na, 35C1, 39K , 79Br, 87Rb and 127I have been measured in various alkali and halogen salt powders relative to well defined aqueous solutions. W ith the known shielding constants of some of these solutions the nuclear magnetic shielding constants of the alkali and chlorine nuclei in crystalline powders were evaluated in the atomic reference scale. The theoretical values of ...

stabilizations and atomic level quadrupole coupling constant (cq) properties have been investigated for graphene–like monolayers (g–monolayers) of boron nitride (bn), boron phosphide (bp), aluminum nitride (aln), and aluminum phosphide (alp) structures. to this aim, density functional theory (dft) calculations have been performed to optimize the model structures and also to evaluate the cq para...

mp2 calculations with cc-pvtz basis set were used to analyze intermolecular interactions in f3cx···yli···nccn and f3cx···nccn···liy triads (x = cl, br; y = cn, nc) which are connected via halogen and lithium bonds. those complexes with the role of liy as halogen acceptor and lithium donor show cooperativity with energy values ranging between -1.97 and -2.92 kj mol-1. those complexes with simult...