scholarly journals 2+ States of 8Be

1969 ◽  
Vol 22 (3) ◽  
pp. 293 ◽  
Author(s):  
FC Barker
Keyword(s):  
Excited State ◽  
Phase Shift ◽  
Excited States ◽  
Wave Scattering ◽  
Matrix Theory ◽  
Half Maximum ◽  
R Matrix ◽  
Particle Spectra ◽  
Scattering Phase ◽  
D Wave

Analysis by many-level R-matrix theory of the d-wave "'-'" scattering phase shift suggests the existence of broad 2+ excited states of 8Be, but their properties depend sensitively on the assumed channel radius a2. A simultaneous fit to the 9Be(p, d)8Be deuteron spectrum near the 2, 9 MeV peak requires a2 "'" 7�1 fm, while a simultaneous fit to the ",-particle spectra following 8Li and 8B p-decays requires a2 "'" 6� 7 fm. For the best overall fit with a2 = 6�75 fm, the first 2+ excited state is at 2� 84 MeV excitation energy with a width at half maximum of 1�30 MeV. It is shown that data from other reactions which appeared to give much larger widths for this level can be fitted using the same R-matrix parameters. A second 2+ excited state is obtained at about 9 MeV with a width of about 10 MeV. Properties of the narrow 2+ states at 16�6 and 16�9 MeV are also discussed.

scholarly journals Theσvreflection symmetry in variational R-matrix theory: Application to Rydberg and doubly-excited states of1Σ and1Σ symmetries in diatomic hydrogen

2011 ◽  
Vol 300 ◽  
pp. 012013 ◽  
Author(s):  
Soumaya Bezzaouia ◽  
Fatma Argoubi ◽  
Mourad Telmini ◽  
Christian Jungen
Keyword(s):  
Excited States ◽  
Matrix Theory ◽  
R Matrix ◽  
Doubly Excited States ◽  
Doubly Excited ◽  
Theory Application

scholarly journals 0+ States of 8Be

1968 ◽  
Vol 21 (3) ◽  
pp. 239 ◽  
Author(s):  
FC Barker ◽  
HJ Hay ◽  
PB Treacy
Keyword(s):  
Excited State ◽  
Excited States ◽  
Cross Section ◽  
Scattering Data ◽  
Excitation Energies ◽  
R Matrix ◽  
Channel Radius

The light even nuclei with A ;;;. 10 have 0+ excited states near 6 MeV, probably with large (X-particle reduced widths. A similar state in BBe would be very broad. Evidence for 0+ excited states in BBe has been obtained here using many-level R-matrix fits to known (X-(X scattering data, but the excitation energies depend strongly on the assumed channel radius. For a simultaneous fit to the 9Be(p, d)BBe cross section, assuming these higher states are not strongly populated, the channel radius is restricted to (7~~) fm, implying a 0+ excited state at (6=f3) MeV of width (9=f4) MeV.

Nucleon and Deuteron Reduced Widths of the Positive Parity (T = 1/2) States of the Mass-5 System

1971 ◽  
Vol 49 (13) ◽  
pp. 1798-1804 ◽  
Author(s):  
S. Ramavataram ◽  
K. Ramavataram
Keyword(s):  
Phase Shift ◽  
Matrix Theory ◽  
Partial Width ◽  
Wave Functions ◽  
Positive Parity ◽  
Recent Analysis ◽  
R Matrix ◽  
Phase Shift Data ◽  
Range Of Values ◽  
Shift Data

Reduced widths for nucleon and deuteron emission from the positive parity (T = 1/2) states in the region of 16 to 20 MeV excitation in the mass-5 system have been calculated using the R-matrix theory. Shell model wave functions were employed to describe the relevant states. Excellent agreement is obtained with various aspects of the experimental results on the well-established 3/2+ resonance at 16.6 MeV. Values for the proton and deuteron partial widths and the γd2/γp2 ratio for the 1/2+ resonance at 18 MeV and 5/2+ resonance at 20 MeV are presented. The calculated proton partial width for the 5/2+ resonance is in the range of values estimated from recent analysis of the p–4He phase-shift data.

scholarly journals I=2ππS-wave scattering phase shift from lattice QCD

2012 ◽  
Vol 85 (3) ◽  
Author(s):  
S. R. Beane ◽  
E. Chang ◽  
W. Detmold ◽  
H. W. Lin ◽  
T. C. Luu ◽  
...  
Keyword(s):  
Phase Shift ◽  
Lattice Qcd ◽  
Wave Scattering ◽  
Scattering Phase

scholarly journals Delayed Alpha Spectra from the Beta Decay of 8Li and 8B

1989 ◽  
Vol 42 (1) ◽  
pp. 25 ◽  
Author(s):  
FC Barker
Keyword(s):  
Phase Shift ◽  
Shell Model ◽  
Satisfactory Agreement ◽  
Beta Decay ◽  
Matrix Elements ◽  
R Matrix ◽  
Intruder State ◽  
Parameter Values ◽  
Gamow Teller ◽  
D Wave

Many-level R-matrix fits are made to the ()(-()( scattering d-wave phase shift and to ()(-spectra from BLi and BB ,8-decay measured by Wilkinson and Alburger (1971). With the requirement that the parameter values are the same in the fits to the phase shift and the ()(-spectra data, the best overall fits are obtained for a channel radius of about 6�5 fm, implying a broad 2+ intruder state of BBe at about 9 MeV. There is satisfactory agreement between the Gamow-Teller matrix elements extracted from the fits and shell model values.

Excited-State Dynamics in the RNA Nucleotide Uridine 5’-Monophosphate Investigated by Femtosecond Broadband Transient Absorption Spectroscopy

2019 ◽  
Author(s):  
Matthew M. Brister ◽  
Carlos Crespo-Hernández
Keyword(s):  
Excited State ◽  
Excited States ◽  
Ground State ◽  
Transient Absorption ◽  
Electronic Energy ◽  
Transient Absorption Spectroscopy ◽  
Electronic Relaxation ◽  
Vibrationally Excited ◽  
Excited State Dynamics ◽  
Π State

<p></p><p> Damage to RNA from ultraviolet radiation induce chemical modifications to the nucleobases. Unraveling the excited states involved in these reactions is essential, but investigations aimed at understanding the electronic-energy relaxation pathways of the RNA nucleotide uridine 5’-monophosphate (UMP) have not received enough attention. In this Letter, the excited-state dynamics of UMP is investigated in aqueous solution. Excitation at 267 nm results in a trifurcation event that leads to the simultaneous population of the vibrationally-excited ground state, a longlived <sup>1</sup>n<sub>O</sub>π* state, and a receiver triplet state within 200 fs. The receiver state internally convert to the long-lived <sup>3</sup>ππ* state in an ultrafast time scale. The results elucidate the electronic relaxation pathways and clarify earlier transient absorption experiments performed for uracil derivatives in solution. This mechanistic information is important because long-lived nπ* and ππ* excited states of both singlet and triplet multiplicities are thought to lead to the formation of harmful photoproducts.</p><p></p>

The Malleable Excited States of Benzothiadiazole Dyes and Investigation of their Potential for Photochemical Control

2019 ◽  
Author(s):  
Caroline C. Warner ◽  
andrea thooft ◽  
Bryan J. Lampkin ◽  
selin demirci ◽  
Brett VanVeller
Keyword(s):  
Excited State ◽  
Excited States ◽  
Polar Solvent ◽  
Nonpolar Solvent ◽  
Photochemical Degradation ◽  
Solvent Lead ◽  
Environmentally Sensitive

<p>A strategy to control the efficiency of a photocleavage reaction based on changing the nature of the excited state is presented. A novel class of photoactive compounds has been synthesized by combining the classical o-nitrobenzyl scaffold with an environmentally sensitive dye, 4-amino-nitrobenzothiazole. Irradiation in a polar solvent lead to an excited state that is inoperative for photochemistry whereas excitation in a nonpolar solvent lead to an excited state that is photochemically active. A photochemical degradation appears to be the preferred process in contrast to the intended photocleavage process.</p>

Excited State Tracking During the Relaxation of Coordination Compounds

2018 ◽  
Author(s):  
Juan Sanz García ◽  
Martial Boggio-Pasqua ◽  
Ilaria Ciofini ◽  
Marco Campetella
Keyword(s):  
Excited State ◽  
Excited States ◽  
Potential Energy Surfaces ◽  
Photochemical Reactions ◽  
Complex Nature ◽  
Electronic Excited States ◽  
Ruthenium Nitrosyl ◽  
State Tracking ◽  
Energy Surfaces ◽  
Electronic Wavefunction

<div>The ability to locate minima on electronic excited states (ESs) potential energy surfaces (PESs) both in the case of bright and dark states is crucial for a full understanding of photochemical reactions. This task has become a standard practice for small- to medium-sized organic chromophores thanks to the constant developments in the field of computational photochemistry. However, this remains a very challenging effort when it comes to the optimization of ESs of transition metal complexes (TMCs), not only due to the presence of several electronic excited states close in energy, but also due to the complex nature of the excited states involved. In this article, we present a simple yet powerful method to follow an excited state of interest during a structural optimization in the case of TMC, based on the use of a compact hole-particle representation of the electronic transition, namely the natural transition orbitals (NTOs). State tracking using NTOs is unambiguously accomplished by computing the mono-electronic wavefunction overlap between consecutive steps of the optimization. Here, we demonstrate that this simple but robust procedure works not only in the case of the cytosine but also in the case of the ES optimization of a ruthenium-nitrosyl complex which is very problematic with standard approaches.</div>

Conduction electron surface scattering phase shift in lead

1979 ◽  
Vol 9 (4) ◽  
pp. L83-L84 ◽  
Author(s):  
A A Cottey
Keyword(s):  
Phase Shift ◽  
Conduction Electron ◽  
Surface Scattering ◽  
Scattering Phase

scholarly journals Ground- and excited-state characteristics in photovoltaic polymer N2200

RSC Advances ◽  
2021 ◽  
Author(s):  
Guanzhao Wen ◽  
Xianshao Zou ◽  
Rong Hu ◽  
Jun Peng ◽  
Zhifeng Chen ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Excited State ◽  
Steady State ◽  
Excited States ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Time Dependent ◽  
Functional Theory ◽  
Time Resolved ◽  
Dependent Density

Ground- and excited-states properties of N2200 have been studied by steady-state and time-resolved spectroscopies as well as time-dependent density functional theory calculations.

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