共查询到20条相似文献,搜索用时 500 毫秒
1.
Y. A. Gauduel Y. Glinec J.-P. Rousseau F. Burgy V. Malka 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,60(1):121-135
The damages triggered by ionizing radiation on chemical and biological targets depend on the survival probability of radicals
produced in clusters of ionization-excitation events. In this paper, we report on femtolysis (FEMTOsecond radioLYSIS) of pure
liquid water using an innovative laser produced high-energy, ultra-short electron bunches in the 2.5-15 MeV range and high
energy radiation femtochemistry (HERF) measurements. The short-time monitoring of a primary reducing radical, hydrated electron
e-aq^{-}_{aq}, has been performed in confined ionization spaces (nascent spurs). The calculated yield of hydrated electrons at early time,
G(e-aq)ETG({\rm e}^{-}_{aq})_{ET}, is estimated to be 6.5 ± 0.5 (number/100 eV) at t ~ 5 ps after the ultrafast energy deposition. This estimated value is high compare to (i) the available data of previous
works that used scavenging techniques; (ii) the predictions of stochastic water radiolysis modelling for which the initial
behaviour of hydrated electron is investigated in the framework of a classical diffusion regime of independent pairs. The
HERF developments give new insights into the early ubiquitous radical escape probability in nascent aqueous spurs and emphasize
the importance of short-lived solvent bridged electron-radical complexes
[H3O+...{\rm H}_{3}{\rm O}^{+...}
eaq-{\rm e}_{aq}^{-} ..OH]nH2O{\rm OH}]_{n{\rm H}_2{\rm O}}
(non-independent pairs). A complete understanding of the
G(e-aq)ET{\rm e}^{-}_{aq})_{ET} value needs to account for quantum aspects of 1s-like trapped electron ground state and neoformed
prototropic radicals that govern ultra-fast recombination processes within these non-independent pair configurations. Femtolysis
data
emphasize that within a time-dependent non-diffusion regime, spatio-temporal correlations between hydrated electron and nearest
neighbours OH radical or hydrated proton (H3O+{\rm H}_{3}{\rm O}^{+}) would assist ultrafast anisotropic 1D recombination within solvent bridged electron-radical complexes. The emerging HERF
domain would provide guidance for understanding of ultrashort-lived sub-structure of tracks and stimulate future semi-quantum
simulations on prethermal radical reactions. 相似文献
2.
Zhi-Gang Wang Zhi-Cheng Liu Xiao-Hong Zhang 《The European Physical Journal C - Particles and Fields》2009,64(3):373-386
In this article, we assume that there exist scalar D*[`(D)]*{D}^{\ast}{\bar {D}}^{\ast}, Ds*[`(D)]s*{D}_{s}^{\ast}{\bar{D}}_{s}^{\ast}, B*[`(B)]*{B}^{\ast}{\bar {B}}^{\ast} and Bs*[`(B)]s*{B}_{s}^{\ast}{\bar{B}}_{s}^{\ast} molecular states, and study their masses using the QCD sum rules. The numerical results indicate that the masses are about
(250–500) MeV above the corresponding D
*–[`(D)]*{\bar{D}}^{\ast}, D
s
*–[`(D)]s*{\bar {D}}_{s}^{\ast}, B
*–[`(B)]*{\bar{B}}^{\ast} and B
s
*–[`(B)]s*{\bar {B}}_{s}^{\ast} thresholds, the Y(4140) is unlikely a scalar Ds*[`(D)]s*{D}_{s}^{\ast}{\bar{D}}_{s}^{\ast} molecular state. The scalar D*[`(D)]*D^{\ast}{\bar{D}}^{\ast}, Ds*[`(D)]s*D_{s}^{\ast}{\bar{D}}_{s}^{\ast}, B*[`(B)]*B^{\ast}{\bar{B}}^{\ast} and Bs*[`(B)]s*B_{s}^{\ast}{\bar{B}}_{s}^{\ast} molecular states maybe not exist, while the scalar D¢*[`(D)]¢*{D'}^{\ast}{\bar{D}}^{\prime\ast}, Ds¢*[`(D)]s¢*{D}_{s}^{\prime\ast}{\bar{D}}_{s}^{\prime\ast}, B¢*[`(B)]¢*{B}^{\prime\ast}{\bar{B}}^{\prime\ast} and Bs¢*[`(B)]s¢*{B}_{s}^{\prime\ast}{\bar{B}}_{s}^{\prime\ast} molecular states maybe exist. 相似文献
3.
Toshiyuki Gogami 《Few-Body Systems》2013,54(1-4):391-394
We have been performing Λ hypernuclear spectroscopic experiments by the (e,e′K +) reaction since 2000 at Thomas Jefferson National Accelerator Facility (JLab). The (e,e′K +) experiment can achieve a few 100 keV (FWHM) energy resolution compared to a few MeV (FWHM) by the (K ?, π ?) and (π +, K +) experiments. Therefore, more precise Λ hypernuclear structures can be investigated by the (e,e′K +) experiment. ${^{7}_{\Lambda}{\rm He}}$ , ${^{9}_{\Lambda}{\rm Li}}$ , ${^{10}_{\Lambda}{\rm Be}}$ , ${^{12}_{\Lambda}{\rm B}}$ , ${^{28}_{\Lambda}{\rm Al}}$ , and ${^{52}_{\Lambda}{\rm V}}$ were measured in the experiment at JLab Hall-C. In addition, ${^{9}_{\Lambda}{\rm Li}}$ , ${^{12}_{\Lambda}{\rm B}}$ , and ${^{16}_{\Lambda}{\rm N}}$ were measured in the experiment at JLab Hall-A. 相似文献
4.
《The European Physical Journal C - Particles and Fields》2004,37(4):421-431
The Pauli exclusion principle (PEP) has been tested for nucleons (n,p) in
and
nuclei, using the results of background measurements with the prototype of the Borexino detector, the Counting Test Facility (CTF). The approach consisted of a search for
, n, p and/or
s emitted in a non-Paulian transition of 1P- shell nucleons to the filled 1S
1/2 shell in nuclei. Similarly, the Pauli-forbidden
decay processes were searched for. Due to the extremely low background and the large mass (4.2 tons) of the CTF detector, the following most stringent up-to-date experimental bounds on PEP violating transitions of nucleons have been established:
,
,
,
,
and
, all at
C.L.Received: 18 June 2004, Published online: 1 October 2004PACS:
11.30.-j, 24.80. + y, 23.20.-g, 27.20. + nG. Bellini: SpokesmanL. Cadonati: Now at Massachusetts Institute of Technology, NW17-161, 175 Albany St. Cambridge, MA 02139O. Dadoun: Marie Curie fellowship at LNGS
Correspondence to: A. Derbin. On leave of absence from St. Petersburg Nuclear Physics Inst. - Gatchina, RussiaM. Deutsch: DeceasedR. Ford: No w at Sudbury Neutrino Observatory, INCO Creighton Mine, P.O.Box 159 Lively, Ontario, Canada, P3Y 1M3B. Freudiger: Marie Curie fellowship at LNGS. Now at Institute for Nuclear Physics, Forschungszentrum Karlsruhe, Postfach 3640, 76021 KarlsruheS. Gazzana: GLIMOSV.V. Kobychev: Now at Institute for Nuclear Research, Prospekt Nauki 47, MSP 03680, Kiev, UkraineG. Korga: On leave of absence from KFKI-RMKI, Konkoly Thege ut 29-33 H-1121 Budapest, HungaryC. Lendvai: Marie Curie fellowship at LNGSP. Lombardi: Detector installation managerA. Martemianov: DeceasedV. Muratova: On leave of absence from St. Petersburg Nuclear Physics Inst. - Gatchina, RussiaL. Niedermeier: Marie Curie fellowship at LNGSL. Papp: On leave of absence from KFKI-RMKI, Konkoly Thege ut 29-33 H-1121 Budapest, HungaryR.S. Raghavan: Present Address: Department of Physics, Virginia Polytechnic Institute and State University, Blacksburg VA 24061G. Ranucci: Project managerC. Salvo: Operational manager
Correspondence to: O. SmirnovA. Sonnenschein: Center for Cosmological Physics, University of Chicago, 933 E.56th St., Chicago, IL 60637 相似文献
5.
J. Stanzel F. Burmeister M. Neeb 《Applied Physics A: Materials Science & Processing》2010,100(1):21-29
We have studied the dynamics of photoexcited tungsten cluster anions Wn-\mathrm{W}_{n}^{-} (n=3,4,…,14) by means of time-resolved two-photon photodetachment spectroscopy. At an excitation energy of h
ν
pump=1.56 eV the photoinduced dynamics is mainly dominated by fast electronic relaxation processes. For the smallest clusters,
i.e., W3-\mathrm{W}_{3}^{-}, W4-\mathrm{W}_{4}^{-}, and W5-\mathrm{W}_{5}^{-}, individual relaxation channels have been identified and resolved on a timescale well below 100 fs. The time constants for
the decay of nascent and secondary electrons have been deduced from a Bloch model. Complete thermalization takes place for
all clusters on a timescale of ∼1 ps. 相似文献
6.
R. Riahi Ph. Teulet Z. Ben Lakhdar A. Gleizes 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(1):61-66
The weighted total cross section (WTCS) theory has been applied to the
electron-H2 collision to obtain excitation, ionisation and dissociation
cross section and rate coefficients of the X 1Sg+^{1}\!\Sigma _{g}^{+}, c
3Pu^{3}\!\Pi _{u}, a 3Sg+^{3}\!\Sigma _{g}^{+}, e $^{3}\!\Sigma
_{u}^{+}$^{3}\!\Sigma
_{u}^{+} and B′
1Su+^{1}\!\Sigma _{u}^{+} states. Calculation has
been performed in the temperature range 1500 K–15000 K. Rate coefficients
are calculated from WTCS assuming Maxwellian energy distribution functions
for electrons and heavy particles. Thermal equilibrium results are presented
and fitting parameters (a, b and c) are given for each reaction rate
coefficient: k(θ) = a (θb)
exp(-c/θ). 相似文献
7.
In this article, we study the Λ
c
and Λ
b
baryons in the nuclear matter using the QCD sum rules, and obtain the in-medium masses
M\varLambda c*=2.335 GeVM_{\varLambda _{c}}^{*}=2.335~\mathrm{GeV},
M\varLambda b*=5.678 GeVM_{\varLambda _{b}}^{*}=5.678~\mathrm{GeV}, the in-medium vector self-energies
\varSigma \varLambda cv=34 MeV\varSigma ^{\varLambda _{c}}_{v}=34~\mathrm{MeV},
\varSigma \varLambda bv=32 MeV\varSigma ^{\varLambda _{b}}_{v}=32~\mathrm {MeV}, and the in-medium pole residues
l\varLambda c*=0.021 GeV3\lambda_{\varLambda _{c}}^{*}=0.021~\mathrm{GeV}^{3},
l\varLambda b*=0.026 GeV3\lambda_{\varLambda _{b}}^{*}=0.026~\mathrm{GeV}^{3}. The mass-shifts are
M\varLambda c*-M\varLambda c=51 MeVM_{\varLambda _{c}}^{*}-M_{\varLambda _{c}}=51~\mathrm{MeV} and
M\varLambda b*-M\varLambda b=60 MeVM_{\varLambda _{b}}^{*}-M_{\varLambda _{b}}=60~\mathrm{MeV}, respectively. 相似文献
8.
Combined constraints on modified Chaplygin gas model from cosmological observed data: Markov Chain Monte Carlo approach 总被引:1,自引:0,他引:1
We use the Markov Chain Monte Carlo method to investigate a global constraints on the modified Chaplygin gas (MCG) model as
the unification of dark matter and dark energy from the latest observational data: the Union2 dataset of type supernovae Ia
(SNIa), the observational Hubble data (OHD), the cluster X-ray gas mass fraction, the baryon acoustic oscillation (BAO), and
the cosmic microwave background (CMB) data. In a flat universe, the constraint results for MCG model are, Wbh2 = 0.02263+0.00184-0.00162 (1s)+0.00213-0.00195 (2s){\Omega_{b}h^{2}\,{=}\,0.02263^{+0.00184}_{-0.00162} (1\sigma)^{+0.00213}_{-0.00195} (2\sigma)}, Bs = 0.7788+0.0736-0.0723(1s)+0.0918-0.0904 (2s){B_{s}\,{=}\,0.7788^{+0.0736}_{-0.0723}(1\sigma)^{+0.0918}_{-0.0904} (2\sigma)}, a = 0.1079+0.3397-0.2539 (1s)+0.4678-0.2911 (2s){\alpha\,{=}\,0.1079^{+0.3397}_{-0.2539} (1\sigma)^{+0.4678}_{-0.2911} (2\sigma)}, B = 0.00189+0.00583-0.00756(1s)+0.00660-0.00915 (2s){B\,{=}\,0.00189^{+0.00583}_{-0.00756}(1\sigma)^{+0.00660}_{-0.00915} (2\sigma)}, and H0=70.711+4.188-3.142 (1s)+5.281-4.149(2s){H_{0}=70.711^{+4.188}_{-3.142} (1\sigma)^{+5.281}_{-4.149}(2\sigma)}. 相似文献
9.
A. Ehresmann W. Kielich L. Werner Ph. V. Demekhin D. V. Omel''yanenko V. L. Sukhorukov K.-H. Schartner H. Schmoranzer 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2007,45(2):235-246
Dispersed fluorescence from fragments formed after the de-excitation of the
1s-1π* resonances of N*O and NO* has been
measured in the spectral range of 118–142 nm. This range is dominated by
lines of atomic nitrogen and oxygen fragments and by the
bands in the NO+ ion which result from the participator Auger decay of the 1s-1π* resonances.
Ab-initio calculations of the transition probabilities between vibrational
levels during the reaction NO
N*O
⇒ NO
were used to explain the observed intensity dependence for the
fluorescence bands on the exciting-photon energy across
the resonances and on both v′ and v′′
vibrational quantum numbers. The multiplet structure of the 1s-1π* resonance and lifetime vibrational interference explain the observed exciting-photon energy dependence of the
fluorescence
intensity. A strong spin-orbit coupling between singlet and triplet states
of NO+ is proposed to reduce additional cascade population of the
state via radiative transitions from the
and
states and to explain
remaining differences between measured and calculated integral fluorescence
intensities. 相似文献
10.
The identification of the fougerite mineral responsible for the bluish-green shade of gleysols in aquifers as being the FeII???III oxyhydroxycarbonate $\text{GR}(\text{CO}_{3}^{2-})^*$ of formula, $[\text{Fe}^{\rm II}_{6x}\text{Fe}^{\rm III}_{6(1 - x)}\text{O}_{12}\text{H}_{2(7-3x)}]^{2+}\bullet[\text{CO}_{3}^{2-}\bullet3\text{H}_{2}\text{O}]^{2-}$ where the ferric molar ratio x = [FeIII/Fetotal] is restricted to the domain [1/3–2/3] induces to study the reactivity of the synthetic green rust for reducing some major pollutants. The oxidation within the solid compound $\text{GR}(\text{CO}_{3}^{2-})^*$ in the presence of nitrates is followed by miniaturized Mössbauer spectrometer (MIMOS). Ratio x = [FeIII/Fetotal] increases up to 0.67 where $\text{GR}(\text{CO}_{3}^{2-})^*$ transforms gradually into magnetite. This could well explain the composition variability of fougerite occurrences. 相似文献
11.
This paper utilizes multireference configuration interaction theory to calculate the lifetime of A2Πu state for nitrogen molecular ion N+2.It obtains the transition moment function for A2Πu→X2Σ+ g,Franck-Condon factors between vibrational levels of the two states.The calculated lifetimes are 16.81,14.62,13.10,12.18,11.40,and 11.64 μs forv'= 0,1,2,3,4,5 vibrational levels of A2Πu state,respectively,which are in excellent agreement with available experimental values. 相似文献
12.
Zhi-song Yu Gui-hua Ren Hong-yi Fan Gen-Chang Cai Nian-Quan Jiang 《International Journal of Theoretical Physics》2012,51(7):2256-2261
We find that the Fock space projector |n〉〈n| is a Weyl ordered Laguerre polynomial 2 ::(-)nLn ( 4afa ) e-2afa ::2{\,}^{:}_{:}(-)^{n}L_{n} ( 4a^{\dagger}a ) e^{-2a^{\dagger}a}{\,}^{:}_{:}, where a † a is the number operator,:: ::,{}^{:}_{:}\ {}^{:}_{:} denotes the Weyl ordering symbol. This brings convenience to derive the Wigner functions of many other quantum states. 相似文献
13.
L. Museur A.V. Kanaev M.C. Castex L. Moussavizadeh R. von Pietrowski T. Möller 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》1999,7(1):73-78
Charge-transfer reactions are observed in a photoluminescence study of NF3\rm NF_3-doped free krypton clusters. They show up in emissions from Kr+F-\rm Kr^{+}F^{-}free excimers ejected from the clusters, and from excited Kr2+F-\rm Kr_2^{+}F^{-}and Kr2+(NF3)m-{\rm Kr}_2^{+}({\rm NF}_3)_m^{-} (m 3(m\geq 1) solvated in the clusters. The results show that reaction dynamics in clusters differs considerably from that in the gas and solid phases. 相似文献
14.
15.
Zhi-Gang Wang 《The European Physical Journal C - Particles and Fields》2009,63(1):115-122
In this article, we assume that there exists a scalar
Ds*[`(D)]s*D_{s}^{\ast}{\bar{D}}_{s}^{\ast}
molecular state in the J/ψ
φ invariant mass distribution, and we study its mass using the QCD sum rules. The predictions depend heavily on the two criteria
(pole dominance and convergence of the operator product expansion) of the QCD sum rules. The value of the mass is about
MDs*[`(D)]s*=(4.43±0.16)M_{D_{s}^{\ast}{\bar{D}}_{s}^{\ast}}=(4.43\pm0.16)
GeV, which is inconsistent with the experimental data. The
Ds*[`(D)]s*D_{s}^{\ast}{\bar{D}}_{s}^{\ast}
is probably a virtual state and is not related to the meson Y(4140). Another possibility, such as a hybrid charmonium, is not excluded. 相似文献
16.
J. J. Camacho M. Santos L. Díaz L. J. Juan J. M. L. Poyato 《Applied Physics A: Materials Science & Processing》2010,99(1):159-175
A spectroscopic study of ambient air plasma, initially at room temperature and pressures ranging from 32 to 101 kPa, produced
by high-power transverse excitation atmospheric (TEA) CO2 laser (λ=9.621 and 10.591 μm; τ
FWHM≈64 ns; power densities ranging from 0.29 to 6.31 GW cm−2) has been carried out in an attempt to clarify the processes involved in laser-induced breakdown (LIB) air plasma. The strong
emission observed in the plasma region is mainly due to electronic relaxation of excited N, O and ionic fragments N+. The medium-weak emission is due to excited species O+, N2+, O2+, C, C+, C2+, H, Ar and molecular band systems of N
2+(_{2}^{+}(
B
2\varSigma u+^{2}\varSigma _{\mathrm{u}}^{+}
–X
2\varSigma g+)^{2}\varSigma _{\mathrm{g}}^{+})
, N2(C3
Π
u–B3
Π
g), N
2+(_{2}^{+}(
D2
Π
g–A2
Π
u) and OH(A2
Σ
+–X2
Π). Excitation temperatures of 23400±700 K and 26600±1400 K were estimated by means of N+ and O+ ionic lines, respectively. Electron number densities of the order of (0.5–2.4)×1017 cm−3 and (0.6–7.5)×1017 cm−3 were deduced from the Stark broadening of several ionic N+ and O+ lines, respectively. Estimates of vibrational and rotational temperatures of N
2+_{2}^{+}
electronically excited species are reported. The characteristics of the spectral emission intensities from different species
have been investigated as functions of the air pressure and laser irradiance. Optical breakdown threshold intensities in air
at 10.591 μm have been measured. 相似文献
17.
To understand the role of isospin effects on fragmentation due to the collisions of charge asymmetric nuclei, we have performed a complete systematical study using isospin-dependent quantum molecular dynamics model. Here simulations have been carried out for $^{124}{\rm X}_{n}+^{124}{\rm X}_{n}$ , where n varies from 47 to 59 and for $^{40}{\rm Y}_{m}+^{40}{\rm Y}_{m}$ , where m varies from 14 to 23. Our study shows that isospin-dependent cross-section shows its influence on fragmentation in the collision of neutron-rich nuclei. 相似文献
18.
L. Pereira A. Morozov M. M. Fraga T. Heindl R. Krücken J. Wieser A. Ulrich 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2010,56(3):325-334
The temperature dependences of the quenching rate constants of the states
N2 (${\rm C} \ {^{3}{
\rm \Pi }_{u}}${\rm C} \ {^{3}{
\rm \Pi }_{u}} v′=0,1) by N2 (X) and of the state
N2 (${\rm C} \ {^{3}{
\rm \Pi }_{u}} \ v^{\prime}=0${\rm C} \ {^{3}{
\rm \Pi }_{u}} \ v^{\prime}=0) by O2 (X) are studied.
Time-resolved light emission from the gas was analyzed in the temperature
range from 300 K to 210 K keeping the gas at constant density. In case of
quenching by N2 (X), the quenching rate constant for the vibrational
level v′= 0 increases by (13 ±3)% with gas cooling whereas the
quenching rate constant for v′= 1 decreases by (5.0 ±2.5)% in this
temperature range. For quenching by O2 (X), the quenching rate constant
decreases by (3 ±2)% with gas cooling. The temperature variation of
the N2 (C 3Πu v′=0) emission intensity for pure nitrogen
and dry air are calculated using the obtained quenching rate constants and
is compared with the experimental data available in the literature. 相似文献
19.
Huailiang Xu Tomoya Okino Kaoru Yamanouchi 《Applied Physics A: Materials Science & Processing》2011,104(3):941-945
Ultrafast delocalization of hydrogen atoms in allene (CH2=C=CH2) induced by intense laser fields was investigated by the Coulomb explosion coincidence momentum imaging method. On the basis
of the kinetic energy distributions of the fragment ions produced through the two three-body Coulomb explosion pathways, C3H43+ ? H+ + CH+ + C2H2+\mathrm{C}_{3}\mathrm{H}_{4}^{3+} \rightarrow \mathrm{H}^{+} + \mathrm{CH}^{+} + \mathrm{C}_{2}\mathrm{H}_{2}^{+} and C3H43+ ? H+ + C2H+ +CH2+\mathrm{C}_{3}\mathrm{H}_{4}^{3+} \rightarrow \mathrm{H}^{+} + \mathrm{C}_{2}\mathrm{H}^{+} +\mathrm{CH}_{2}^{+}, and the proton maps for both pathways, it was shown that the decomposition proceeds in a stepwise manner as well as in a
concerted manner. The time scale of the hydrogen migration within an allene molecule was estimated to be ∼20 fs. 相似文献
20.
J. Moc 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,61(2):397-402
We have studied the interaction of Al13-_{13}^{-} anion
cluster with H2. Both the long range interaction and dissociative
adsorption have been examined using the established correlated ab initio
methods, MP2 and CCSD(T), in conjunction with the augmented correlation
consistent basis sets up to aug-cc-pVTZ. The formation of the weakly bound
(physisorbed) end-on anion complex Al13-_{13}^{-}...H2 is
predicted for the interacting Al...H distances of 3.95 ? with the
H-H axis pointing towards the ‘hollow’ site of Al13-_{13}^{-} and binding
energy (De)D_{e}) of 0.7 kcal/mol at the estimated complete basis set (CBS)
limit of CCSD(T). The barrier height for H2 dissociation on
Al13-_{13}^{-} of 41.6 (42.9) kcal/mol calculated at the ZPVE-corrected
CCSD(T)/aug-cc-pVTZ (estimated CCSD(T)/CBS) level is at least twice as large
as that evaluated by us for a dissociative adsorption of H2 on an
open-shell Al13 neutral cluster. To our knowledge, this report presents
the first “benchmark” quality study of the physisorption and dissociative
chemisorption of molecular hydrogen on Al13-_{13}^{-} anion cluster. 相似文献