共查询到20条相似文献,搜索用时 31 毫秒
1.
Electron‐Nuclear Dynamics in Molecular Harmonic Generation Driven by a Plasmonic Nonhomogeneous Field 下载免费PDF全文
Electron (z)‐nuclear (R) dynamics in the molecular high‐order harmonic generation (MHHG) from H2+ driven by the plasmonic nonhomogeneous field, generated by the surface plasmon polaritons in the bowtie‐shaped nanostructure, have been theoretically investigated through solving the two dimensional time‐dependent Schrödinger equation with the Non‐Bohn‐Oppenheimer approximation. It is found that (i) due to the plasmonic enhancement of the laser intensity, the harmonic cutoff can be extended when the spatial position of H2+ is away from the gap center of the nanostructure. However, due to the limit of the gap size, the threshold value of the harmonic cutoff can be obtained at a given position of H2+. (ii) Due to the asymmetric enhancement of the laser intensity in space, the extended higher harmonics are respectively from E(t) > 0 a.u. or E(t) < 0 a.u. for the cases of the positive and the negative spatial position of H2+. As a result, the intensities of the extended higher harmonics are different and can be controlled by changing the carrier‐envelope phase and the pulse duration of the laser field. (iii) In the few‐cycle pulse duration, the MHHG mainly comes from the multi‐photon resonance ionization (MPRI), while as the pulse duration increases, the MPRI, the charge‐resonance enhanced ionization (CREI) and even the dissociative ionization (DI) are contributed to the MHHG. Moreover, as the spatial position of H2+ moves, the contributions of the MHHG from the MPRI, the CERI and the DI can be controlled. (iv) The contributions of the MHHG from the two‐H nuclei have been investigated and found that when E(t) > 0 a.u., the intensities of the harmonics from the negative‐H is higher than those from the positive‐H; while when E(t) < 0 a.u., the intensities of the harmonics from the positive‐H plays the main role in the MHHG. Moreover, the multi‐minima, caused by the two‐center interference can also be found. (v) Finally, by superposing a properly selected harmonics, a single isolated attosecond pulse (SIAP) with the full width at half maximum (FWHM) of 34 as can be obtained. 相似文献
2.
High diastereoselectivity induced by intermolecular hydrogen bonding in [3 + 2] cycloaddition reaction: experimental and computational mechanistic approaches 下载免费PDF全文
A diastereoselective [3 + 2] cycloaddition of N‐aryl substituted maleimides with N,α‐diphenyl nitrone possessing 11‐hydroxyundecyloxy as a flexible substituent was performed. Experimental and comprehensive mechanistic density functional theory studies reveals that intermolecular H‐bonding and steric repulsive interaction predominate exo‐Z and exo‐E cycloaddition transition states, respectively. The reaction proceeded smoothly depending on the reactants and gave a good yield of (syn) cis‐isoxazolidine or (anti) trans‐isoxazolidine as a single diastereomer. 相似文献
3.
Anilinolysis of O‐butyl phenyl phosphonochloridothioate in acetonitrile: Synthesis,characterization, kinetic study,and reaction mechanism 下载免费PDF全文
This paper describes a simple optimized method for the synthesis of O‐butyl phenyl phosphonochloridothioate ( 4 ) under mild conditions. The target compounds were characterized by 1H‐nuclear magnetic resonance (NMR), 13C‐NMR, and 31P‐NMR spectroscopy, as well as mass spectroscopy. The apparent structure of 4 was confirmed by optimization using the B3LYP/6‐311 + G(d,p) level in the Gaussian 09 program in acetonitrile. The nucleophilic substitution reactions of 4 with X‐anilines (XC6H4NH2) and deuterated X‐anilines (XC6H4ND2) were investigated kinetically in acetonitrile at 55.0°C. The free energy relationship with X in the anilines looked biphasic concave upwards with a break region between X = H and X = 3‐MeO, giving large negative ρX and small positive βX values. The deuterium kinetic isotope effects were secondary inverse (kH/kD < 1: 0.789‐0.995) and the magnitudes, (kH/kD), increased when the nucleophiles were changed from weakly basic to strongly basic anilines. A concerted SN2 mechanism is proposed on the basis of the selectivity parameters and the variation trend of the deuterium kinetic isotope effects with X. 相似文献
4.
Complexation of bis‐crown stilbene with alkali and alkaline‐earth metal cations. Ultrafast excited state dynamics of the stilbene‐viologen analogue charge transfer complex 下载免费PDF全文
Valery V. Volchkov Mikhail V. Rusalov Fedor E. Gostev Ivan V. Shelaev Viktor A. Nadtochenko Artem I. Vedernikov Asya A. Efremova Lyudmila G. Kuz'mina Sergey P. Gromov Michael V. Alfimov Mikhail Ya. Melnikov 《Journal of Physical Organic Chemistry》2018,31(2)
The complex formation of bis(18‐crown‐6)stilbene ( 1 ) and its supramolecular donor‐acceptor complex with N,N′‐bis(ammonioethyl) 1,2‐di(4‐pyridyl)ethylene derivative ( 2 ) with alkali and alkaline‐earth metal perchlorates has been studied using absorption, steady‐state fluorescence, and femtosecond transient absorption spectroscopy. The formation of 1 ?Mn+ and 1 ?(Mn+)2 complexes in acetonitrile was demonstrated. The weak long‐wavelength charge‐transfer absorption band of 1 · 2 completely vanishes upon complexation with metal cations because of disruption of the pseudocyclic structure. The spectroscopic and luminescence parameters, stability constants, and 2‐stage dissociation constants were calculated. The initial stage of a recoordination process was found in the excited complexes 1 ?M+ and 1 ?(M+)2 (M = Li, Na). The pronounced fluorescence quenching of 1 · 2 is explained by very fast back electron transfer (τet = 0.397 ps). The structure of complex 1 · 2 was studied by X‐ray diffraction; stacked ( 1 · 2 )m polymer in which the components were connected by hydrogen bonding and stacking was found in the crystal. These compounds can be considered as novel optical molecular sensors for alkali and alkaline‐earth metal cations. 相似文献
5.
Mohammad Zaman Kassaee Maryam Koohi Reza Mohammadi Monireh Ghavami 《Journal of Physical Organic Chemistry》2013,26(11):908-916
Replacement of α‐methylenes with BH, AlH, CMe2, SiH2, NH, NMe, NtButyl, NPh, PH, O, and S in non‐planar cyclonona‐3,5,7‐trienylidene (CH2) alters its status from an unstable transition state to rather stable minima, at B3LYP/6‐311++G**//B3LYP/6‐31 + G* levels of theory. All species appear with singlet closed shell (Scs) global minima, except for SiH2 and CH2 which exhibit triplet electronic ground states. The order of stability based on singlet–triplet energy gap (ΔEs–t / kcalmol?1) is: CMe2 (45.8) > NH (35.8) > NMe (32.3) > O (31.5) > NtButyl (27.7) ≥ NPh (27.5) ≥ BH (27.4) > S (21.9) > PH (17.0) > CH2 (?4.4) > SiH2 (?12.5). In contrast to many reports on N‐heterocyclic carbenes, here alkyl groups appear to exert a higher stabilizing effect than heteroatoms, making CMe2 the most stable. In addition bulky NMe, NtButyl, and NPh appear more nucleophilic than their synthesized imidazol‐2‐ylidene congeners. Excluding SiH2, isodesmic reactions reveal that all substituents stabilize singlet state considerably more than the corresponding triplet. Finally, this work is hoped to pave the path for future matrix isolations and IR studies of these rather stable cyclic non‐planar carbenes. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
6.
S. Leenhardt O. Sorlin M.G. Porquet F. Azaiez J.C. Angélique M. Belleguic C. Borcea C. Bourgeois J.M. Daugas C. Donzaud I. Deloncle J. Duprat A. Gillibert S. Grévy D. Guillemaud-Mueller J. Kiener M. Lewitowicz S.M. Lukyanov F. Marie N.A. Orr Yu.-E. Penionzhkevich F. de Oliveira Santos F. Pougheon M.G. Saint-Laurent W. Shuying Yu. Sobolev J.S. Winfield 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):1-5
The reduced transition probability B(E2: 01
+→ 2+) of 72Zn has been measured for the first time by Coulomb excitation at intermediate energy. The result B(E2: 01
+→ 2+) = 1740±210 e2fm4, corresponds to the deformation parameter β2 of 0.23, in close agreement with expectations derived from the neighboring nucleus 73Zn. A discussion of the evolution of the N = 40 sub-shell closure as a function of Z is presented.
Received: 19 December 2001 / Accepted: 14 March 2002 相似文献
7.
Klaudia Jakusová Jana Donovalová Martin Gáplovský Marek Cigáň Henrieta Stankovičová Anton Gáplovský 《Journal of Physical Organic Chemistry》2013,26(10):805-813
The self‐association and tautomerism of (E)‐isatin‐3‐4‐phenyl(semicarbazone) Ia and (E)‐N‐methylisatin‐3‐4‐phenyl(semicarbazone) IIa were investigated in solvents of various polarity. In weakly interacting non‐polar solvents, such as CHCl3 and benzene, phenylsemicarbazone concentrations above 1×10?5 mol dm?3 result in the formation of dimers or higher aggregates of E‐isomers Ia and IIa . This aggregate formation prevents room temperature E–Z isomerization of Ia and IIa to more stable Z‐isomers. In contrast to the situation in non‐polar solvents, E–Z isomerization from the monomeric form of phenylsemicarbazone Ia and IIa E‐isomers occurs in highly interactive polar solvents including MeOH and DMF only at temperatures above 70 °C. Moreover, decrease in phenylsemicarbazone concentration below 1×10?4 mol dm?3 in these highly solute–solvent interacting systems leads to aggregate dissociation, and a new hydrazonol tautomeric form with a high degree of conjugation predominates in these solutions. Theoretical calculations confirm obtained experimental results. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
8.
Petr K. Sazonov Galina A. Artamkina Irina P. Beletskaya 《Journal of Physical Organic Chemistry》2008,21(3):198-206
Second order rate constants are reported for the reactions of metal carbonyl anions ([M(CO)nL]?) with several vinyl halides: PhCCl?C(CN)2, Z‐ and E‐Ph(CN)C?CHHal (Hal = Cl, Br) which follow the addition–elimination (AdNE) substitution mechanism. The obtained data show that the nucleophilic reactivity of [M(CO)nL]? anions towards vinyl halides increases in the same order as in aliphatic SN2 reactions, but much more steeply, by 14 orders of magnitude in the row log{ }: [CpFe(CO)2]? (~14), [Re(CO)5]? (7.8), [Mn(CO)5]? 2.1, [CpW(CO)3]? (0.7) > [CpMo(CO)3]? (0). A good correlation exists between nucleophilicities of [M(CO)nL]? anions towards vinyl (sp2‐carbon) and alkyl halides (sp3‐carbon) with slope 2.7. The reactivity of [M(CO)nL]? in a halogen–metal exchange process (with Z‐PhC(CN)?CHI) follows a similar ‘large’ scale as in the AdNE process. The nucleophilicity of [M(CO)nL]? anions correlates better with their one‐electron oxidation potentials (Eox) than with their basicity (pKa of [M(CO)nL]H). Copyright © 2008 John Wiley & Sons, Ltd. 相似文献
9.
We analyze the long time behavior of solutions of the Schrödinger equation ${i\psi_t=(-\Delta-b/r+V(t,x))\psi}We analyze the long time behavior of solutions of the Schr?dinger equation iyt=(-D-b/r+V(t,x))y{i\psi_t=(-\Delta-b/r+V(t,x))\psi},
x ? \mathbbR3{x\in\mathbb{R}^3}, r = |x|, describing a Coulomb system subjected to a spatially compactly supported time periodic potential V(t, x) = V(t + 2π/ω, x) with zero time average. 相似文献
10.
Jagbir Singh Harjeet Kaur Arvind Sharma J. Goswamy D. Mehta Nirmal Singh R. K. Bhowmik P. N. Trehan 《Zeitschrift für Physik A Hadrons and Nuclei》1995,351(2):125-126
Two new neutron-deficient isotopes,213Pa and214Pa were produced in complete fusion reactions of51V-ions with170Er targets at (5.2–5.6) AMeV. The assignment was based on delayed evaporation residue - - time and position coincidences. The- decay energies of213,214Pa were measured to be E=(8236±20) keV and E=(8116±20) keV, respectively. The half-lives of213,214Pa were determined to be T1/2=(5.3
–1.6
+4.0
ms and T1/2=(17 ±3) ms, respectively.This article was processed by the author using the LATEX style filecljour2 from Springer-Verlag. 相似文献
11.
Kinetics and thermodynamics of reversible disproportionation–comproportionation in redox triad oxoammonium cations – nitroxyl radicals – hydroxylamines 下载免费PDF全文
Vasily D. Sen’ Ivan V. Tikhonov Leonid I. Borodin Evgeny M. Pliss Valery A. Golubev Mikhail A. Syroeshkin Alexander I. Rusakov 《Journal of Physical Organic Chemistry》2015,28(1):17-24
Kinetics and equilibrium of the acid‐catalyzed disproportionation of cyclic nitroxyl radicals R2NO? to oxoammonium cations R2NO+ and hydroxylamines R2NOH is defined by redox and acid–base properties of these compounds. In a recent work (J. Phys. Org. Chem. 2014, 27, 114‐120), we showed that the kinetic stability of R2NO? in acidic media depends on the basicity of the nitroxyl group. Here, we examined the kinetics of the reverse comproportionation reaction of R2NO+ and R2NOH to R2NO? and found that increasing in –I‐effects of substituents greatly reduces the overall equilibrium constant of the reaction K4. This occurs because of both the increase of acidity constants of hydroxyammonium cations K3H+ and the difference between the reduction potentials of oxoammonium cations ER2NO+/R2NO? and nitroxyl radicals ER2NO?/R2NOH. pH dependences of reduction potentials of nitroxyl radicals to hydroxylamines E1/3Σ and bond dissociation energies D(O–H) for hydroxylamines R2NOH in water were determined. For a wide variety of piperidine‐ and pyrrolidine‐1‐oxyls values of pK3H+ and ER2NO+/R2NO? correlate with each other, as well as with the equilibrium constants K4 and the inductive substituent constants σI. The correlations obtained allow prediction of the acid–base and redox characteristics of redox triads R2NO?–R2NO+–R2NOH. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献
12.
Summary A search has been made for excesses of cosmic-ray counting rates at primary energiesE
01>5 GeV andE
04>2·104 GeV over the time scalet=(1÷100) ms. The measurement was performed by means of a small extensive air shower array operating at mountain altitude (3500
m a.s.l.). During the running time 111 cosmic gamma-ray bursts were detected by satellites; 10 of them certainly (55 probably)
above the horizon of the detector. No significant counting rate excess has been recorded out of the statistical fluctuations.
Also the search for correlations with satellite events has given a negative result. The upper limit for high-energy cosmic
gamma-ray flux in bursts isϕ
1(E>E
01)<4·10−5 (t = time scale in ms),ϕ
4(E>E
04)<1.6·10−5erg/cm2.
Paper presented at the 2o Convegno Nazionale di Fisica Cosmica, held at L'Aquila, 29 May–2 June 1984. 相似文献
13.
Ryszard B. Nazarski 《Journal of Physical Organic Chemistry》2007,20(6):422-430
The study of an isomeric A / B mixture of the title oxime 1 , by photolytic or thermal E,Z‐isomerization and NMR measurement including 1H{1H}‐NOE difference spectra, led to assignment of the E configuration to its predominating form A . The 1H/13C data were interpreted in terms of steric overcrowding of both forms, especially of the thermolabile photoproduct B . Four classical (empirical) NMR methods of elucidating the oxime geometry were critically tested on these results. Unexpected vapor‐phase photoconversion A → B in the window glass‐filtered solar UV and spectroscopic findings on their protonated states were discussed, as well. The kinetically controlled formation of the N‐protonated species (Z)‐ 5 + was proved experimentally. In addition, some 1H NMR assignments reported for structurally similar systems were rationalized ( 3 and 4 ) or revised ( 1 and 7–9 ) with the GIAO‐DFT(B3LYP) and/or GIAO‐HF calculational results. Copyright © 2007 John Wiley & Sons, Ltd. 相似文献
14.
C?t?lin I. Carstea 《Communications in Mathematical Physics》2010,300(2):487-528
The existence of co-rotational finite time blow up solutions to the wave map problem from ${\mathbb{R}^{2+1} \to N}The existence of co-rotational finite time blow up solutions to the wave map problem from
\mathbbR2+1 ? N{\mathbb{R}^{2+1} \to N} , where N is a surface of revolution with metric d
ρ
2 + g(ρ)2
dθ2, g an entire function, is proven. These are of the form u(t,r)=Q(l(t)t)+R(t,r){u(t,r)=Q(\lambda(t)t)+\mathcal{R}(t,r)} , where Q is a time independent solution of the co-rotational wave map equation −u
tt
+ u
rr
+ r
−1
u
r
= r
−2
g(u)g′(u), λ(t) = t
−1-ν, ν > 1/2 is arbitrary, and R{\mathcal{R}} is a term whose local energy goes to zero as t → 0. 相似文献
15.
Zhi-Gang Wang 《The European Physical Journal C - Particles and Fields》2009,59(3):675-681
In this article, we assume that there exist hidden charmed tetraquark states with spin–parity J
P=1−, and we calculate their masses with the QCD sum rules. The numerical result indicates that the masses of the vector hidden
charmed tetraquark states are about M
Z
=(5.12±0.15) GeV or M
Z
=(5.16±0.16) GeV, which are inconsistent with the experimental data on the π
+
χ
c1 invariant-mass distribution. The hidden charmed mesons Z
1, Z
2 or Z may be scalar hidden charmed tetraquark states, hadro-charmonium resonances or molecular states. 相似文献
16.
The level structures populated in alpha decay of all odd-Z-even-N nuclei withZ=(83–93) andN=(126–142) up to 500 keV are presented. More data on the 4n+3 nuclear sequences are given from215Bi to235Np. Particular emphasis is placed on the hindrance factors to alpha decay in interpreting the level structures in term of
the shell model, the octupole-quadrupole model and the Nilsson model. The level structures and the hindrance factors go through
transition region in which mixtures of the properties of two different nuclear models are appropriate. These transition regions
represent a challenge to nuclear theorists to develop more all-encompassing nuclear models. 相似文献
17.
M. Bender T. Cornelius G.A. Lalazissis J.A. Maruhn W. Nazarewicz P.-G. Reinhard 《The European Physical Journal A - Hadrons and Nuclei》2002,14(1):23-28
Recent mass measurements show a substantial weakening of the binding-energy difference δ2p(Z, N) = E(Z - 2, N) - 2E(Z, N) + E(Z + 2, N) in the neutron-deficient Pb isotopes. As δ2p is often attributed to the size of the proton magic gap, it might be speculated that reduction in δ2p is related to a weakening of the spherical Z = 82 shell. We demonstrate that the observed trend is described quantitatively by self-consistent mean-field models in terms
of deformed ground states of Hg and Po isotopes.
Received: 25 October 2001 / Accepted: 28 February 2002 相似文献
18.
U. D. Jentschura B. J. Wundt 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2011,65(3):357-366
The current discrepancy of theory and experiment observed recently in muonic hydrogen
necessitates a reinvestigation of all corrections to contribute to the Lamb shift in
muonic hydrogen (μH), muonic deuterium (μD), the muonic
\hbox{3He{}^3{\rm He}}
3
He
ion (denoted here as μ
3He+), as well as in the muonic
\hbox{4He{}^4{\rm He}}
4
He
ion (μ
4He+). Here, we choose a semi-analytic approach and evaluate a
number of higher-order corrections to vacuum polarization (VP) semi-analytically, while
remaining integrals over the spectral density of VP are performed numerically. We obtain
semi-analytic results for the second-order correction, and for the relativistic correction
to VP. The self-energy correction to VP is calculated, including the perturbations of the
Bethe logarithms by vacuum polarization. Subleading logarithmic terms in the
radiative-recoil correction to the 2S–2P Lamb shift of order
α(Zα)5
μ
3ln(Zα) / (m
μ
m
N
)
are also obtained. All calculations are nonperturbative in the mass ratio of orbiting
particle and nucleus. 相似文献
19.
《X射线光谱测定》2006,35(1):52-56
As a result of a systematic analysis of the compilation of McMaster's x‐ray cross‐sections, the polynomial coefficients of the N range (from edges N7 to M5) of elements Z = 61–69 have to be corrected. Furthermore, no detailed information on position and jumps of M edges of elements Z > 53 and N edges of elements Z > 85 are given. Elements Z = 84, 85, 87, 88, 89, 91 and 93 are missing. We have corrected the wrong values of polynomial coefficients and added missing M‐ and N‐edge data and missing elements. Copyright © 2005 John Wiley & Sons, Ltd. 相似文献
20.
H. H. Hansen 《Zeitschrift für Physik A Hadrons and Nuclei》1979,291(1):43-47
Accurate experimental internal conversion data have been used to study the effect of nuclear penetration in the case of thel-forbidden transitions in139La (165.8 keV),141Pr (145.4 keV) and203Tl (279.2 keV). The nuclear penetration parameterλ and theE2/M 1 mixing ratioδ 2 have been deduced by graphical analysis. Following results were obtained:λ=2.8±1.3,δ 2 =(8.4 ?8.4 +14.0 )·10?4 for139La,λ=1.2±0.6,δ 2=(4.8±0.5)·10?3 for141Pr, andλ=6.4±1.1,δ 2=1.36±0.12 for203Tl. 相似文献