scholarly journals Simple models for the quick estimation of ground state hydrogen tunneling splittings in alcohols and other compounds

2021 ◽  
Author(s):  
Robert Medel
Keyword(s):  
Experimental Data ◽  
Ground State ◽  
Hydrogen Tunneling ◽  
Hydrogen Atoms ◽  
Tunneling Splittings ◽  
Coherent Tunneling ◽  
Simple Models

Models for the quick estimation of energy splittings caused by coherent tunneling of hydrogen atoms are evaluated with available experimental data for alcohols and improvements are proposed. The discussed models...

scholarly journals Emission of Fast Hydrogen Atoms in a Low Density Gas Discharge—The Most “Natural” Mirror Laboratory

Atoms ◽  
2019 ◽  
Vol 7 (3) ◽  
pp. 81
Author(s):  
Oleksandr Marchuk ◽  
Sven Dickheuer ◽  
Stephan Ertmer ◽  
Yuri Krasikov ◽  
Philippe Mertens ◽  
...  
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
Ground State ◽  
Low Density ◽  
Hydrogen Atoms ◽  
Time Resolved ◽  
Line Shapes ◽  
Strong Signal ◽  
Balmer Lines ◽  
The Doppler Effect

In this work, we present a new application for the line shapes of emission induced by reflected hydrogen atoms. Optical properties of the solids in contact with the plasma could be effectively measured at the wavelength of Balmer lines: time-resolved measurements of reflectance and polarization properties of mirrors are performed using the wavelength separation of the direct and reflected signals. One uses the Doppler effect of emission of atoms excited by collisions with noble gases, primarily with Ar or with Kr. In spite of a new application of line shapes, the question of the source of the strong signal in the case of Ar exists: the emission observed in the case of the excitation of H or D atoms by Ar exceeds the signal induced by collisions with Kr atoms by a factor of five, and the only available experimental data for the ground state excitation show practically equal cross-sections for both gases in the energy range of 80–200 eV.

Simple theoretical models of elimination reactions on polar catalysts; Dehydration reactivity of secondary alcohols on acidic and basic catalysts

1985 ◽  
Vol 50 (4) ◽  
pp. 920-929 ◽  
Author(s):  
Jiří Sedláček
Keyword(s):  
Experimental Data ◽  
Quantum Chemical ◽  
Theoretical Models ◽  
Aliphatic Alcohols ◽  
Secondary Alcohols ◽  
Carbonium Ion ◽  
Dehydration Reactions ◽  
Aromatic Alcohols ◽  
Basic Catalysts ◽  
Simple Models

CNDO/2 calculations for simple models of adsorption and dehydration reactions of secondary aliphatic and aromatic alcohols on polar catalysts are presented. The models involve selected stages of elimination mechanisms of various types (E1, E2 and E1cB elimination). Calculated quantum chemical quantities were correlated with reported experimental data. It is shown that reactivities for the series of substituted phenylethanols correlate very well with the ease of carbonium ion formation. In the case of aliphatic alcohols, calculated quantities correlate generally with the reactivities on SiO2 and are in anticorrelation with the reactivities on Al2O3.NaOH.

scholarly journals THE METHOD OF INCREMENTS — A WAVEFUNCTION-BASED AB-INITIO CORRELATION METHOD FOR SOLIDS

2007 ◽  
Vol 21 (13n14) ◽  
pp. 2204-2214 ◽  
Author(s):  
BEATE PAULUS
Keyword(s):  
Experimental Data ◽  
Ab Initio ◽  
Ground State ◽  
Infinite System ◽  
Correlation Energy ◽  
Correlation Method ◽  
Many Body ◽  
Hartree Fock ◽  
The Many ◽  
Good Agreement

The method of increments is a wavefunction-based ab initio correlation method for solids, which explicitly calculates the many-body wavefunction of the system. After a Hartree-Fock treatment of the infinite system the correlation energy of the solid is expanded in terms of localised orbitals or of a group of localised orbitals. The method of increments has been applied to a great variety of materials with a band gap, but in this paper the extension to metals is described. The application to solid mercury is presented, where we achieve very good agreement of the calculated ground-state properties with the experimental data.

scholarly journals Calculations of the decay transitions of the modified Pöschl–Teller potential model via Bohr Hamiltonian technique

2017 ◽  
Vol 26 (11) ◽  
pp. 1750073 ◽  
Author(s):  
Nahid Soheibi ◽  
Majid Hamzavi ◽  
Mahdi Eshghi ◽  
Sameer M. Ikhdair
Keyword(s):  
Experimental Data ◽  
Ground State ◽  
Potential Model ◽  
Electric Quadrupole ◽  
Numerical Results ◽  
Transition Rates ◽  
Collective Hamiltonian

We calculate the eigenvalues and their corresponding eigenfunctions of the Bohr’s collective Hamiltonian with the help of the modified Pöschl–Teller (MPT) potential model within [Formula: see text]-unstable structure. Our numerical results for the ground state (g.s.) [Formula: see text] and [Formula: see text] band heads, together with the electric quadrupole [Formula: see text] transition rates, are displayed and compared with the available experimental data.

scholarly journals Hole Transfer in Open Carbynes

Materials ◽  
2020 ◽  
Vol 13 (18) ◽  
pp. 3979
Author(s):  
Constantinos Simserides ◽  
Andreas Morphis ◽  
Konstantinos Lambropoulos
Keyword(s):  
Density Functional Theory ◽  
Ground State ◽  
Density Functional ◽  
State Energy ◽  
Frequency Content ◽  
Hydrogen Atoms ◽  
Functional Theory ◽  
Transfer Rates ◽  
Transfer Integrals ◽  
End Groups

We investigate hole transfer in open carbynes, i.e., carbon atomic nanowires, using Real-Time Time-Dependent Density Functional Theory (RT-TDDFT). The nanowire is made of N carbon atoms. We use the functional B3LYP and the basis sets 3-21G, 6-31G*, cc-pVDZ, cc-pVTZ, cc-pVQZ. We also utilize a few Tight-Binding (TB) wire models, a very simple model with all sites equivalent and transfer integrals given by the Harrison ppπ expression (TBI) as well as a model with modified initial and final sites (TBImod) to take into account the presence of one or two or three hydrogen atoms at the edge sites. To achieve similar site occupations in cumulenes with those obtained by converged RT-TDDFT, TBImod is sufficient. However, to achieve similar frequency content of charge and dipole moment oscillations and similar coherent transfer rates, the TBImod transfer integrals have to be multiplied by a factor of four (TBImodt4times). An explanation for this is given. Full geometry optimization at the B3LYP/6-31G* level of theory shows that in cumulenes bond length alternation (BLA) is not strictly zero and is not constant, although it is symmetrical relative to the molecule center. BLA in cumulenic cases is much smaller than in polyynic cases, so, although not strictly, the separation to cumulenes and polyynes, approximately, holds. Vibrational analysis confirms that for N even all cumulenes with coplanar methylene end groups are stable, for N odd all cumulenes with perpendicular methylene end groups are stable, and the number of hydrogen atoms at the end groups is clearly seen in all cumulenic and polyynic cases. We calculate and discuss the Density Functional Theory (DFT) ground state energy of neutral molecules, the CDFT (Constrained DFT) “ground state energy” of molecules with a hole at one end group, energy spectra, density of states, energy gap, charge and dipole moment oscillations, mean over time probabilities to find the hole at each site, coherent transfer rates, and frequency content, in general. We also compare RT-TDDFT with TB results.

scholarly journals Study of sub-barrier fusion of 36S+50Ti,51V systems

2019 ◽  
Vol 223 ◽  
pp. 01013
Author(s):  
Giulia Colucci ◽  
Giovanna Montagnoli ◽  
Alberto M. Stefanini ◽  
Kouichi Hagino ◽  
Antonio Caciolli ◽  
...  
Keyword(s):  
Experimental Data ◽  
Comparative Study ◽  
Excitation Function ◽  
Ground State ◽  
Weak Coupling ◽  
Coupling Scheme ◽  
Excitation Functions ◽  
Coupled Channels ◽  
Barrier Distribution ◽  
Good Agreement

A detailed comparative study of the sub-barrier fusion of the two near-by systems 36S+50Ti,51V was performed at the National Laboratories of Legnaro (INFN). Aim of the experiment was the investigation of possible effects of the non-zero spin of the ground state of the 51V nucleus on the sub-barrier excitation function, and in particular on the shape of the barrier distribution. The results sh w that the two measured excitation functions are very similar down to the level of 20 - 30 μb. The same is observed for the two barrier distributions. Coupled-channels calculations have been performed and are in good agreement with the experimental data. This result indicates that the low-lying levels in 51V can be interpreted in the weak-coupling scheme, that is, 51V(I) = 50Ti(2+)⊗ p(1 f7/2).

Determination of hyperon properties through the variational method considering the hyperfine interaction

2019 ◽  
Vol 28 (10) ◽  
pp. 1950087 ◽  
Author(s):  
S. M. Moosavi Nejad ◽  
A. Armat
Keyword(s):  
Experimental Data ◽  
Wave Function ◽  
Ground State ◽  
Radiative Decay ◽  
Magnetic Moments ◽  
Wave Functions ◽  
Decay Widths ◽  
Free Parameters ◽  
Theoretical Results

Performing a fit procedure on the hyperon masses, we first determine the free parameters in the Cornell-like hypercentral potential between the constituent quarks of hyperons in their ground state. To this end, using the variational principle, we apply the hyperspherical Hamiltonian including the Cornell-like hypercentral potential and the perturbation potentials due to the spin–spin, spin–isospin and isospin–isospin interactions between constituent quarks. In the following, we compute the hyperon magnetic moments as well as radiative decay widths of spin-3/2 hyperons using the spin-flavor wave function of hyperons. Our analysis shows acceptable consistencies between theoretical results and available experimental data. This leads to reliable wave functions for hyperons at their ground state.

Cluster expansion of the wavefunction. Potential energy curves of the ground, excited, and ionized states of Li2

1985 ◽  
Vol 63 (7) ◽  
pp. 1857-1863 ◽  
Author(s):  
H. Nakatsuji ◽  
J. Ushio ◽  
T. Yonezawa
Keyword(s):  
Experimental Data ◽  
Potential Energy ◽  
Cluster Expansion ◽  
Ground State ◽  
Spectroscopic Properties ◽  
Bound State ◽  
Potential Energy Curves ◽  
Interaction Theory ◽  
Theoretical Results ◽  
S States

The SAC (symmetry-adapted-cluster) and SAC-CI theories based on the cluster expansion of the wavefunction have been applied to the calculations of the potential energy curves of the ground, excited, and ionized states of the Li2 molecule. The potential energy curves and the spectroscopic properties calculated agree well with the available experimental data and the previous theoretical results of Olson and Konowalow. For the [Formula: see text] state, our calculation is the first and predicts a bound state whose minimum is at Re = 6.8 bohr and 2.5 eV above the ground state. This state dissociates into 2P and 2S states of the Li atoms and has a hump which is higher than and outside of the hump of the B1IIu state. The long-range behavior of the states which dissociate into 2P and 2S states of the Li atom is well predicted by the resonance interaction theory.

Influences of Trace Water in Hydrogen and Argon on the Tribological Properties of Pure Iron

2012 ◽  
Author(s):  
Kanao Fukuda ◽  
Masaaki Hashimoto ◽  
Joichi Sugimura
Keyword(s):  
Experimental Data ◽  
Tribological Properties ◽  
Pure Iron ◽  
Synergy Effect ◽  
Hydrogen Atoms ◽  
Wear Rates ◽  
Hydrogen Environment ◽  
Trace Water ◽  
Nascent Surface

Tribological properties of pure iron were studied in argon environments containing trace water which is controlled at the value between 1 and 10,000 ppb and virtually no oxygen. The experimental data were compared with those obtained in our previous study with the same conditions of experiment but in hydrogen. The influences of trace water were recognized in both gases and confirmed not peculiar to a hydrogen environment. The coefficients of friction and specific wear rates were different to some extent between argon and hydrogen environments. The differences were supposed to be attributed to the influences of hydrogen atoms which chemisorbed on pure iron atoms appeared on the nascent surface made by sliding. Whether hydrogen and water have synergy effect on influencing tribological properties was not clarified in this study.

scholarly journals The Nonlinear Dispersion Relation and the Relationship of the Forming Soliton Area to the Evolution of Pulsars

1987 ◽  
Vol 125 ◽  
pp. 461-461 ◽  
Author(s):  
Mao Xinjie ◽  
Tong Yi
Keyword(s):  
Electric Field ◽  
Ground State ◽  
Nonlinear Effects ◽  
Electric Polarization ◽  
Nonlinear Dispersion ◽  
Hydrogen Atoms ◽  
Nonlinear Dispersion Relation ◽  
Relationship Of ◽  
The Relationship ◽  
The Universe

Based on Zakharov's equations, Karpman et al. claimed that there were solitons in the magnetosphere. According to the model proposed by Goldreich and Julin, there is a strong induced electric field in the magnetosphere. It seems that we should include the nonlinear effects of the electric field on the polarization of hydrogen atoms if there really are some hydrogen atoms spreading in the magnetosphere of the pulsar. Assuming the magnetosphere is symetric, therefore the electric polarization of hydrogen atoms is of the form P=χ(1)E +χχE3. We treat χ(1) and χ(2) as scalars because most hydrogen atoms in the universe are in the ground state and χ(3) is much smaller than χ(1).

Sign in / Sign up

Export Citation Format

Share Document