scholarly journals Differential steric effects in the inelastic scattering of NO(X) + Ar: spin–orbit changing transitions

2019 ◽  
Vol 21 (26) ◽  
pp. 14173-14185 ◽  
Author(s):  
M. Brouard ◽  
S. D. S. Gordon ◽  
B. Nichols ◽  
V. Walpole ◽  
F. J. Aoiz ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Steric Effect ◽  
Steric Effects ◽  
Spin Orbit ◽  
First Time

The differential steric effect for spin–orbit changing collisions of NO with Ar is determined for the first time.

scholarly journals Steric effects and quantum interference in the inelastic scattering of NO(X) + Ar

2015 ◽  
Vol 6 (4) ◽  
pp. 2202-2210 ◽  
Author(s):  
B. Nichols ◽  
H. Chadwick ◽  
S. D. S. Gordon ◽  
C. J. Eyles ◽  
B. Hornung ◽  
...  
Keyword(s):  
Inelastic Scattering ◽  
Quantum Interference ◽  
Steric Effect ◽  
Steric Effects

New measurements of the differential steric effect for NO + Ar inelastic scattering highlight the importance of quantum interference.

Le spectre des états électroniques de Kr I mesuré par spectrométrie électronique

1975 ◽  
Vol 53 (19) ◽  
pp. 2079-2084 ◽  
Author(s):  
A. Delage ◽  
J.-D. Carette
Keyword(s):  
Experimental Data ◽  
Energy Loss ◽  
Inelastic Scattering ◽  
Electronic States ◽  
Resolving Power ◽  
Electron Spectrometer ◽  
Energy Incident ◽  
First Time ◽  
Electron Energy Loss ◽  
Electron Energy Loss Spectra

The spectrum of electronic states of krypton I has been measured by inelastic scattering of monoenergetic electrons with the aid of an electron spectrometer which has a high resolving power, ΔE/E = 0.02. Electron energy loss spectra have allowed us to detect and identify numerous electronic states of krypton I for the first time by the means of this experimental method. The relative heights of the peaks corresponding to an energy loss, which are related to the probability of excitation of the atom by electron impact to a given state, have been measured from experimental data as a function of the energy incident electrons and as a function of the scattering angle.

scholarly journals Study of Kinetics, Equilibrium and the Influence of Steric Effects on Proton-Transfer in the Reactions of 2, 2, 4- and 2, 6- Substituted Anilines with 2-Phenoxy-3,5-dinitropyridine in DMSO

2010 ◽  
Vol 7 (1) ◽  
pp. 253-259 ◽  
Author(s):  
Basim H. Asghar
Keyword(s):  
Proton Transfer ◽  
Steric Effect ◽  
Nucleophilic Attack ◽  
Steric Effects ◽  
Substituted Anilines ◽  
Phenoxy Group ◽  
Kinetics Studies ◽  
Zwitterionic Intermediate ◽  
Rate Limiting ◽  
Step Mechanism

Kinetic and equilibrium results for the reactions of 2-phenoxy-3,5-dinitropyridine (1), with a series of 2, 2, 4- and 2, 6- substituted anilines (2a-f), in the presence of DABCO in DMSO are reported. The reactions yield the 2-anilino derivatives (5), without the accumulation of intermediates. Kinetics studies are compatible with a two-step mechanism involving initial nucleophilic attack by amine at the ring carbon substituted by phenoxy group followed by either base-catalyzed or uncatalyzed conversion to the product. The base-catalyzed pathway is likely to involve rate-limiting proton-transfer from the zwitterionic intermediate to base. This work indicates a steric effect to proton transfer in reactions involving 2, 6-disubstituted anilines. The results were compared with those for reactions of 1, 3, 5-trinitrobenzene with anilines.

Excitation function for α-particle-induced reactions in light-mass nuclei

1993 ◽  
Vol 71 (3-4) ◽  
pp. 115-121 ◽  
Author(s):  
N. L. Singh ◽  
S. Agarwal ◽  
J. Rama Rao
Keyword(s):  
High Resolution ◽  
Inelastic Scattering ◽  
Excitation Function ◽  
Low Energy ◽  
Activation Technique ◽  
Scattering Effects ◽  
Foil Activation ◽  
Stacked Foil Activation Technique ◽  
First Time ◽  
Existing Data

The excitation functions of 51V [(α, xn), x = 1.3; (α, p3n); (α, α3n) (α, 2α)] and 59Co[(α, 2n); (α, αxn); x = 1, 2] reactions were measured up to 50 MeV by the stacked-foil activation technique and high-resolution Ce(Li)–HPGe spectroscopy method. Of these 51V(α, xnypzα) reactions were studied for the first time with better accuracy than earlier measurements, which were done with a poor resolution scintillation–Ge(Li) detectors some 20 years ago. In the case of 59Co, existing data show large discrepancies at low energy. Comparisons are presented with the prediction of hybrid and exciton models. While for the (α, xn) type of reactions, reasonably explainable pre-equilibrium contributions are found, there seem to be indications of direct inelastic scattering effects in the (α, αxn) type of reactions.

Elastic and inelastic scattering of 40 MeV polarized protons from 90Zr and 92Zr

1979 ◽  
Vol 57 (4) ◽  
pp. 540-549 ◽  
Author(s):  
R. de Swiniarski ◽  
Dinh-Lien Pham ◽  
G. Bagieu ◽  
H. V. Geramb
Keyword(s):  
Inelastic Scattering ◽  
Cross Sections ◽  
Imaginary Component ◽  
Spin Orbit ◽  
Model Calculations ◽  
Analyzing Powers ◽  
Elastic And Inelastic Scattering ◽  
Polarized Protons ◽  
The Cross ◽  
Good Agreement

Analyzing powers and cross sections have been measured for elastic and inelastic scattering of 40 MeV polarized protons from 90Zr and 92Zr. The analysis has been carried out in the DWBA within the framework of the macroscopic and microscopic models. Furthermore, the coupled-channels calculations using the vibrational model and the full Thomas form for the spin–orbit potential give a very good description for both the cross sections and the analyzing powers of the iow-lying2+, 3−, 5−, and 4+ states in 92Zr and the 2+ and 3− in 90Zr. The cross section and analyzing power for the first 2+ state in these nuclei were compared with previous results at 30 and 20.3 MeV, and from this comparison a certain energy dependence of the relative strength of the spin–orbit deformation to the central deformation could be observed. Microscopic model calculations with tensor and spin–orbit components included in the projectile–target real interaction and with an exact treatment of knock-on' exchange have been performed for the 2+ states in these nuclei. An attempt has also been made in order to include the imaginary component in the N–N interaction. For these calculations, rather good agreement was obtained especially for the 2+ state in 92Zr but poor agreement for 90Zr. Finally, valence plus core polarization calculations have also been done and showed a very good agreement between theory and experiment for those 2+ transitions.

scholarly journals Anisotropy of the static dipole polarizability induced by the spin–orbit interaction: the S-state atoms N–Bi, Cr, Mo and Re

2010 ◽  
Vol 467 (2129) ◽  
pp. 1310-1328 ◽  
Author(s):  
Alexei A. Buchachenko
Keyword(s):  
Cold Atoms ◽  
Orbit Interaction ◽  
Cluster Method ◽  
Fourth Power ◽  
Dipole Polarizability ◽  
Spin Orbit ◽  
Spin Orbit Interaction ◽  
First Time ◽  
Anisotropic Tensor ◽  
Configuration Interaction Calculations

A systematic ab initio study is performed on the ground state static dipole polarizabilities of the 2 S +1 S, S >1/2, atoms from N to Bi, Cr, Mo, Mn, Tc and Re. The benchmark scalar-relativistic values of the scalar polarizability components are obtained using the coupled cluster method. The spin–orbit configuration interaction calculations are carried out for the anisotropic (tensor) polarizability components of these atoms (except Mn and Tc) that arise from the second-order spin–orbit interaction. The tensor polarizabilities are calculated for the first time and found to increase from 10 −5 (N) to 3.8 atomic units (Bi) approximately as the fourth power of the nuclear charge. The simple correlations and implication to magnetic trapping of cold atoms are discussed.

Interaction of Polar Groups with a Bulky Hydrocarbon Residue: Polarizability and Steric Effects

2005 ◽  
Vol 70 (3) ◽  
pp. 370-382 ◽  
Author(s):  
Stanislav Böhm ◽  
Otto Exner
Keyword(s):  
Steric Effect ◽  
Extreme Case ◽  
Steric Effects ◽  
Enthalpies Of Formation ◽  
Straight Chain ◽  
Polar Groups ◽  
Sterically Demanding ◽  
Additive Rule ◽  
Stabilization Energies ◽  
The Individual

Energies of two series of branched hydrocarbon monosubstituted derivatives, 2-substituted 2-methylpropanes and 1-substituted bicyclo[2.2.2]octanes with 19 different substituents were calculated at the B3LYP/6-311+G(d,p) level and compared with the energies of straight-chain 1-substituted butanes. The comparison was carried out in terms of isodesmic homodesmotic reactions, in which the substituent is transferred from one hydrocarbon residue to another. The branched derivatives are mostly stabilized, in the extreme case by as much as 30 kJ mol-1 confirming that the additive rule used for estimating the enthalpies of formation is not valid for branched derivatives. The stabilization energies ∆E for the individual substituents X are not proportional to any known substituent parameters. In the qualitative respect, they are controlled by the first atom of the substituent - similarly as in the straight-chain isomers - but in the case of sterically demanding substituents they are perturbed by a destabilizing steric effect.

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