BREAKUP REACTIONS AND EXOTIC STRUCTURES OF HALO NUCLEI

2009 ◽  
Vol 18 (10) ◽  
pp. 2071-2076
Author(s):  
TAKASHI NAKAMURA ◽  
YOSHITERU SATOU ◽  
TAKASHI SUGIMOTO ◽  
YOSUKE KONDO
Keyword(s):  
Halo Nuclei ◽  
Neutron Decay ◽  
Proton Target ◽  
Excitation Energies ◽  
Decay Threshold ◽  
First Time

We have performed breakup experiments of halo nuclei: 11 Li with a Pb target, 14 Be with 12 C and proton targets, and 19 C on a proton target at approximately 70 MeV/nucleon at RIKEN. These experiments aim at investigating the E1 response of 11 Li , and at searching for the low-lying discrete resonances of 14 Be and 19 C above the neutron decay threshold. The former results shows the strong E1 transitions at low excitation energies (soft E1 excitation), which suggests the spatial neutron-neutron correlation. The latter revealed the first 2+ state of 14 Be , and the second 5/2+ state of 19 C for the first time.

Can boron form coordination complexes with diffuse electrons? Evidence for linked solvated electron precursors

2022 ◽  
Author(s):  
Zachary Jordan ◽  
Shahriar N. Khan ◽  
Benjamin A. Jackson ◽  
Evangelos Miliordos
Keyword(s):  
Electronic Structure ◽  
Density Functional ◽  
Molecular System ◽  
Hydrocarbon Chain ◽  
Solvated Electron ◽  
Excitation Energies ◽  
Functional Theory ◽  
Boron Complexes ◽  
The Stability ◽  
First Time

Abstract Density functional theory and ab initio multi-reference calculations are performed to examine the stability and electronic structure of boron complexes that host diffuse electrons in their periphery. Such complexes (solvated electron precursors or SEPs) have been experimentally identified and studied theoretically for several s- and d-block metals. For the first time, we demonstrate that a p-block metalloid element can form a stable SEP when appropriate ligands are chosen. We show that three ammonia and one methyl ligands can displace two of the three boron valence electrons to a peripheral 1s-type orbital. The shell model for these outer electrons is identical to previous SEP systems (1s, 1p, 1d, 2s). Further, we preformed the first examination of a molecular system consisting of two SEPs bridged by a hydrocarbon chain. The electronic structure of these dimers is very similar to that of traditional diatomic molecules forming bonding and anti-bonding σ and π orbitals. Their ground state electronic structure resembles that of two He atoms, and our results indicate that the excitation energies are nearly independent of the chain length for four carbon atoms or longer. These findings pave the way for the development of novel materials similar to expanded metals and electrides.

Breakup of oxygen nucleus on isotopes of hydrogen and nitrogen nuclei in collisions with protons at 3.25A GeV/c

2016 ◽  
Vol 25 (08) ◽  
pp. 1650060
Author(s):  
Kosim Olimov ◽  
Khusniddin K. Olimov ◽  
Sagdulla L. Lutpullaev ◽  
Alisher K. Olimov ◽  
Vladimir V. Lugovoi ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Cross Section ◽  
Recoil Proton ◽  
Monte Carlo Model ◽  
Phenomenological Analysis ◽  
Isotropic Phase ◽  
Proton Target ◽  
Oxygen Nucleus ◽  
Final State ◽  
First Time

Phenomenological analysis of breakup of oxygen nuclei on fragments with the charges one and seven in collisions with protons at 3.25[Formula: see text][Formula: see text]GeV/[Formula: see text] was conducted using the Monte Carlo model of isotropic phase space. For the first time, the contributions of mechanism of diffractive breakup of oxygen nucleus and that of quasi-elastic knocking out of one of the protons of oxygen nucleus by a proton target into channel of formation of proton fragment and [Formula: see text]N nucleus with conservation of recoil proton in final state were determined. Cross-section of diffractive breakup of oxygen [Formula: see text]O nucleus on [Formula: see text]N nucleus and proton fragment and that of diffractive breakup of [Formula: see text]O nucleus on nuclei [Formula: see text]N and 2H were estimated for the first time in [Formula: see text]O[Formula: see text] collisions at 3.25[Formula: see text][Formula: see text]GeV/[Formula: see text].

Characterization of the unusual metal-free, zinc, chloroindium, and ferrocenylindium 5,10,15,20-tetraferrocenylporphyrin anion-radicals by spectroelectrochemical, DFT, and TDDFT approaches

2012 ◽  
Vol 16 (07n08) ◽  
pp. 793-801 ◽  
Author(s):  
Victor N. Nemykin ◽  
Ping Chen ◽  
Pavlo V. Solntsev ◽  
Anatolii A. Purchel ◽  
Karl M. Kadish
Keyword(s):  
Density Functional ◽  
Broad Band ◽  
Excitation Energies ◽  
Vertical Excitation ◽  
Additional Information ◽  
Vis Spectroscopy ◽  
Controlled Potential ◽  
First Time ◽  
Anion Radicals

Anion-radicals of general formula [MTFcP]- ( M = 2H, Zn, InCl , and InFc; TFcP2- is a dianion of 5,10,15,20-tetraferrocenylporphyrin) were prepared for the first time in situ by controlled potential reduction of the respective neutral MTFcP complexes in a thin layer spectroelectrochemical cell. UV-vis spectroscopy reveals the formation of a broad NIR band between 827–890 nm and another broad band in the Soret region between 458 and 527 nm. A similar NIR band has previously been assigned to 5,10,15,20-tetra(aryl)porphyrin radical-anions. Additional information on the electronic structure and nature of the vertical excitation energies in the [H2TFcP]- system were obtained by density functional theory (DFT) and time-dependent DFT (TDDFT) methods. DFT calculations predict that the SOMO in the [H2TFcP]- anion-radical is predominantly localized over the porphyrin core. TDDFT calculations suggest numerous MLCT transitions in addition to the expected π–π* excitations, which play a key role in the formation of unusual UV-vis spectra in the [MTFcP]- anion-radicals.

Self-Energy corrections to DFT-LDA Gaps of Realistic Carbon Nanotubes

2001 ◽  
Vol 703 ◽  
Author(s):  
Guido Satta ◽  
Giancarlo Cappellini ◽  
Francesco Casula
Keyword(s):  
Carbon Nanotubes ◽  
Band Gap ◽  
Electronic Properties ◽  
Crucial Point ◽  
Excitation Energies ◽  
Self Energy ◽  
Microelectronic Devices ◽  
First Time

ABSTRACTSince their discovery carbon nanotubes have attracted much interest for their peculiar electronic properties which go from metalic to semiconducting behaviour, depending both on diameter and chirality. The exact vaue of their band gap is obviously a crucial point to be addressed because it enters in the nanotube application as microelectronic devices. By making use of an efficient GW scheme, previousy tested on bulk systems, as well as of a model screening function, we obtained for the first time excitation energies and band-gap vaues for carbon nanotubes. Results for (6,0) and (7,0) will be presented and discussed.

CALCULATING MEAN EXCITATION ENERGY FROM SHANNON INFORMATION ENTROPY FOR K–Xe ATOMS

2003 ◽  
Vol 14 (02) ◽  
pp. 221-224
Author(s):  
M. SOLIMANNEJAD ◽  
A. H. PAKIARI
Keyword(s):  
Shannon Entropy ◽  
Information Entropy ◽  
Ground State ◽  
Periodic Table ◽  
Excitation Energies ◽  
Hartree Fock ◽  
Mean Excitation Energy ◽  
Shannon Information Entropy ◽  
The Mean ◽  
First Time

The calculation of the Shannon entropy of Hartree–Fock electron density is reported for the K–Xe atoms in the fourth and fifth rows of the periodic table in the ground state. In local plasma approximation, the Shannon entropy calculated is used directly to estimate mean excitation energies. To our knowledge, the mean excitation energies of K–Xe atoms are presented here for the first time.

scholarly journals Embedding-theory-based simulations using experimental electron densities for the environment

2020 ◽  
Vol 76 (5) ◽  
pp. 571-579
Author(s):  
Niccolò Ricardi ◽  
Michelle Ernst ◽  
Piero Macchi ◽  
Tomasz Adam Wesolowski
Keyword(s):  
Density Functional ◽  
Energy Functional ◽  
Real Space ◽  
Total Density ◽  
X Ray Diffraction ◽  
Excitation Energies ◽  
Embedding Theory ◽  
Multi Level ◽  
First Time ◽  
Electron Wavefunction

The basic idea of frozen-density embedding theory (FDET) is the constrained minimization of the Hohenberg–Kohn density functional E HK[ρ] performed using the auxiliary functional E_{v_{AB}}^{\rm FDET}[\Psi _A, \rho _B], where Ψ A is the embedded N A -electron wavefunction and ρ B (r) is a non-negative function in real space integrating to a given number of electrons N B . This choice of independent variables in the total energy functional E_{v_{AB}}^{\rm FDET}[\Psi _A, \rho _B] makes it possible to treat the corresponding two components of the total density using different methods in multi-level simulations. The application of FDET using ρ B (r) reconstructed from X-ray diffraction data for a molecular crystal is demonstrated for the first time. For eight hydrogen-bonded clusters involving a chromophore (represented as Ψ A ) and the glycylglycine molecule [represented as ρ B (r)], FDET is used to derive excitation energies. It is shown that experimental densities are suitable for use as ρ B (r) in FDET-based simulations.

The absorption spectrum of europium

1976 ◽  
Vol 283 (1313) ◽  
pp. 345-365 ◽  
Keyword(s):  
Absorption Spectrum ◽  
Angular Momentum ◽  
Total Angular Momentum ◽  
Zeeman Effect ◽  
Unknown Origin ◽  
Ground Level ◽  
Excitation Energies ◽  
Sharp Line ◽  
Ionization Limit ◽  
First Time

The europium absorption spectrum has been photographed at high resolution in the spectral region 7200-2100 A which includes the entire sharp-line spectrum longward q£ the first ionization limit. Wavelengths and wavenumbers have been determined by comparison with thorium standards. Since all transitions take place from the ground level the wavenumbers correspond to excitation energies of even-parity levels with total angular momentum ( J)of f , or f . /-values and gj-values have been determined for many of these levels from a study of the longitudinal Zeeman effect in the 5 T (50 kG) field of a superconducting solenoid magnet. The configurations 4f7 (8S) 6s 6p, 4f7 (8g) 6s 7p, 4f7 (8S) 5d 6p and 4f6 (7F) 5d 6s2 are discussed in detail. Levels of 4f6 5d2 6s and 4f7 (6I) 6s 6p are reported for the first time. Several long series and parts of series have been discovered among the highly excited levels. Some of these can be identified with levels arising from 4f7 6s (9S) np and 4f7 6s (7S) np but interpretation is complicated by the presence of several perturbations of unknown origin.

LIFETIME MEASUREMENTS OF EXCITED STATES IN 73As

2004 ◽  
Vol 13 (05) ◽  
pp. 1019-1034 ◽  
Author(s):  
K. P. SINGH ◽  
T. KAKAVAND ◽  
M. HAJIVALIEI
Keyword(s):  
Statistical Theory ◽  
Excited States ◽  
Doppler Shift ◽  
Nuclear Reactions ◽  
Angular Distributions ◽  
Excitation Energies ◽  
Lifetime Measurements ◽  
Mixing Ratios ◽  
Doppler Shift Attenuation ◽  
First Time

The excited states of 73 As have been investigated via the 73 Ge ( p , n γ)73 As reaction with proton beam energies from 2.5–4.3 MeV. The lifetimes of the levels at 769.6, 860.5, 1177.8, 1188.7, 1274.9, 1344.1, 1557.1 and 1975.2 keV excitation energies have been measured for the first time using the Doppler shift attenuation method. The angular distributions have been used to assign the spins and the multipole mixing ratios using statistical theory for compound nuclear reactions. The ambiguity in the spin values for the various levels has been removed. The multipole mixing ratios for eight γ-transitions have been newly measured.

Breakup of 16O nucleus onto C and He isotopes by protons at incident momentum of 3.25AGeV/c

2016 ◽  
Vol 25 (03) ◽  
pp. 1650023 ◽  
Author(s):  
Kosim Olimov ◽  
Khusniddin K. Olimov ◽  
Sagdulla L. Lutpullaev ◽  
Erkin Kh. Bazarov ◽  
Alisher K. Olimov ◽  
...  
Keyword(s):  
Cluster Structure ◽  
Recoil Proton ◽  
Isotropic Phase ◽  
Proton Target ◽  
Oxygen Nucleus ◽  
Final State ◽  
He Isotopes ◽  
Initial Nucleus ◽  
First Time

Phenomenological analysis of breakup of oxygen nuclei on fragments with charges two and six in collisions with protons at [Formula: see text][Formula: see text]GeV/[Formula: see text] was conducted using the Monte Carlo (MC) model of isotropic phase space. For the first time, the contributions of mechanism of diffractive breakup of oxygen nucleus, and that of quasi elastic knocking out of one of the [Formula: see text] clusters of oxygen nucleus by a proton target, into channel of formation of [Formula: see text] particle and [Formula: see text]C nucleus with conservation of recoil proton were determined in final state. The substantial role of [Formula: see text] cluster structure of initial nucleus in processes of fragmentation of oxygen nuclei in peripheral interactions with protons was revealed in experiment.

scholarly journals Equilibrium Geometries, Adiabatic Excitation Energies and Intrinsic C=C/C–H Bond Strengths of Ethylene in Lowest Singlet Excited States Described by TDDFT

Symmetry ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1545
Author(s):  
Yunwen Tao ◽  
Linyao Zhang ◽  
Wenli Zou ◽  
Elfi Kraka
Keyword(s):  
Excited States ◽  
Ground State ◽  
Density Functional ◽  
Excitation Energies ◽  
Functional Theory ◽  
Local Vibrational Mode ◽  
Strength Change ◽  
Bond Strengths ◽  
First Time ◽  
Equilibrium Geometries

Seventeen singlet excited states of ethylene have been calculated via time-dependent density functional theory (TDDFT) with the CAM-B3LYP functional and the geometries of 11 excited states were optimized successfully. The local vibrational mode theory was employed to examine the intrinsic C=C/C–H bond strengths and their change upon excitation. The natural transition orbital (NTO) analysis was used to further analyze the C=C/C–H bond strength change in excited states versus the ground state. For the first time, three excited states including πy′ → 3s, πy′ → 3py and πy′ → 3pz were identified with stronger C=C ethylene double bonds than in the ground state.

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