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1.
A statistical mechanical theory is developed for gas-phase bimolecular (binary) reactions: ABA + B. Based on the activated-complex hypotheses, and expression for the association rate constant ka is derived: ka = k*AB* → AB (QAB*/qA+B), where k*AB* →AB is the rate constant for the transition from the activated state AB* to the molecular state AB, and qx is the equilibrium occupation probability for state X. The three states (AB, AB*, A + B) are defined by three regions of the energyseparation plane for the relative motion of the reactant pair (A, B). If the interatomic potential has a critical barrier ϵc at separation rc and an attractive well with depth ϵbc, ϵb > kBT) computations of the qAB*/qA +B generate an Arrhenius-Boltzmann factor exp (—ϵc/kBT). The virtual rate constant k*AB* →AB is calculated by assuming that the reactant pair reaching the activated state AB* with the separation r < rc and the energy E > c moves on to the molecular state AB only if it loses part of its radial kinetic energy with the aid of third body (catalyst or collision) and is trapped by the potential well. With no catalysts present, this constant is approximately given by k*AB* →ABd2v′ R′−3, where v′ is the thermal center-of-mass speed, and d′ and R′ are respectively the collision-sphere radius and the mean distance between AB* and any molecule (A, B, AB or AB*). For binary dissociation, the rate constant kd is given by kd = k*AB* →A+B qAB*/qAB), which generates exp [—(ϵc + ϵb)/kBT]. A catalyst for binary reaction is assumed to act as a mediator, facilitating the energy exchange between the radial and rotational modes of motion. Additionally for association only, it also acts as a confinement agent, preventing the pair from flying away from each other. Connections with the collision theory and the activated complex theory are discussed critically.  相似文献   

2.
邵丹  邵亮  邵常贵  H.Noda 《物理学报》2007,56(3):1271-1291
对圈量子引力中标架度量矩阵算符对Gauss编织态的作用为本征作用,提供了完整的证明.求得了全部标架度量矩阵算符的表示矩阵,及其期望值.利用自旋几何定理,在内腿颜色k=0和k=2两种情况下,算得了Gauss编织态顶角毗邻的4条腿(P=1)的相位位形切方向间的全部夹角,以及切矢量的长度. 关键词: 度量算符的表示矩阵 度量期望值 切方向间夹角 切矢量长度  相似文献   

3.
郑久仁  霍裕平 《物理学报》1983,32(5):571-581
我们在Oregonator模型的基础上,取速率常数k6、理想配比系数f及波数k为参变量,首先讨论了B-Z反应体系的稳定性,并得到了下列各量的表达式:空间周期结构的临界速率常数k6c、短波临界波数ksc与长波临界波数kLc,时空周期结构的临界速率常数k6c及临界波数kc等。而后,我们给出了B-Z反应体系的临界频率λc,讨论了体系在临界状态附近的行为,并得到了触发波速度uT及相位波速度uP的表达式。本文的结论是,在一定条件下,不搅拌的B-Z反应体系能在临界状态附近呈现稳定的波群或者波包,触发波是均匀体系中的波包,相位波是有微小梯度的非均匀体系中的波包。uT=2ηDkc,D为HBrO2的扩散系数,η为[H+]的缓变函数(在实验观测范围内,η≈0.1);uP=v,v为相速度。 关键词:  相似文献   

4.
Mossbauer studies were performed in 57Fe impurities (0.3% at.) in solid methane, in order to investigate the properties of the order-disorder phase transition taking place at Tc=20.4K. From the temperature dependence of the relative values of the recoil-free-fraction - f - it was found that near Tc a change occurs in the slope of f(T2) without discontinuity in the value of f. A consistent model is proposed by which immediately below Tc both phases, I and II coexist with a gradual evolution of the ordered state (II) on the account of the high temperature plastic state (I). The Debye temperature of phase II (θII = 101±7K) increases with respect to that of phase I (θI = 72±3K), indicating a hardening in the phonon spectrum and precluding the onset of rotational modes of the disordered molecules.  相似文献   

5.
Electron-transfer(ET) from organic sulfides to excited state rhenium(I)-based heteroleptic tricarbonyl complexes [Re(bpy)(CO)3(py)]+ (I) and [Re(bpy)(CO)3(ind))]+ (II) in acetonitrile solution is facile and luminescence quenching constants, kq, are in the range 105–108 M−1s−1. The detection of the sulfide radical cation in this system using time-resolved absorption spectroscopy is a direct evidence for the ET nature of the reaction. The kq values for the quenching of Re(I)-complexes with organic sulfides are analyzed with a scheme involving rate controlling electron transfer process. The measured rate constants for the electron transfer (ET) reaction are close to the values calculated from Marcus theory.  相似文献   

6.
It is shown that if one incorporates the generalized coordinate quantum velocitiesQ 1 as given byQ 1=l[H,Q 1](h=1) into the generalized classical Lagrangian for a free particle (the total energy),L=1/2Q 1 g tk Q k one does not obtain (no matter what ordering of the operatorsq l ,q k andg lkwe choose the correct quantum Lagrangian operator which is a transformation from -1/2V2 to generalized coordinates (Gruber, 1971, 1972).q l as given byq l=i[H,q l] turns out to be the Hermitian part of a more generaiized operator which we call the total generalized velocity operator similar to the notation in ear previous articles (Gruber, 1971, 1972). This total velocity operator really determines the fundamental structure governing our system in the Lagrangian formulation. We show that ft is through the total velocity operator that we make the transition from classical to quantum mechanics and through our procedure we arrive at the correct quantum Lagrangian operator.  相似文献   

7.
A.G. Ramm 《Physics letters. A》2009,373(33):2988-2991
Let A(β,α,k) be the scattering amplitude corresponding to a real-valued potential which vanishes outside of a bounded domain DR3. The unit vector α is the direction of the incident plane wave, the unit vector β is the direction of the scattered wave, k>0 is the wave number. The governing equation for the waves is [∇2+k2q(x)]u=0 in R3. For a suitable class M of potentials it is proved that if Aq1(−β,β,k)=Aq2(−β,β,k),∀βS2, ∀k∈(k0,k1), and q1, q2M, then q1=q2. This is a uniqueness theorem for the solution to the inverse scattering problem with backscattering data. It is also proved for this class of potentials that if , ∀k∈(k0,k1), and q1, q2M, then q1=q2. Here is an arbitrarily small open subset of S2, and |k0k1|>0 is arbitrarily small.  相似文献   

8.
In the framework of a simple spin-boson Hamiltonian we study an interplay between dynamic and spectral roots to stochastic-like behavior. The Hamiltonian describes an initial vibrational state coupled to discrete dense spectrum reservoir. The reservoir states are formed by three sequences with rationally independent periodicities 1; 1 ± δ typical for vibrational states in many nanosize systems (e.g., large molecules containing CH2 fragment chains, or carbon nanotubes). We show that quantum evolution of the system is determined by a dimensionless parameter δΓ, where Γ is characteristic number of the reservoir states relevant for the initial vibrational level dynamics. When δΓ > 1 spectral chaos destroys recurrence cycles and the system state evolution is stochastic-like. In the opposite limit δΓ < 1 dynamics is regular up to the critical recurrence cycle k c and for larger k > k c dynamic mixing leads to quasi-stochastic time evolution. Our semi-quantitative analytic results are confirmed by numerical solution of the equation of motion. We anticipate that both kinds of stochastic-like behavior (namely, due to spectral mixing and recurrence cycle dynamic mixing) can be observed by femtosecond spectroscopy methods in nanosystems in the spectral window 1011–1013 s−1  相似文献   

9.
In this paper, the completeness of the k orthonormalized eigenstates of the operator (a q f(N q )) k (k 3) is proved. We introduce a new kind of higher order squeezing and an antibunching. The properties of the Mth-order squeezing and the antibunching effect of the k states are investigated. The result shows that these states may form a complete Hilbert space, and the Mth order [M = (m + 1/2)k;m = 0,1,2,. . .] squeezing effects exist in all of the k states when k is even. There is the antibunching effect in all of the states.  相似文献   

10.
We study an inverse problem for the two-dimensional random Schrödinger equation (Δ + q + k 2)u = 0. The potential q(x) is assumed to be a Gaussian random function whose covariance operator is a classical pseudodifferential operator. We show that the backscattered field, obtained from a single realization of the random potential q, determines uniquely the principal symbol of the covariance operator of q. The analysis is carried out by combining harmonic and microlocal analysis with stochastic methods.  相似文献   

11.
本文根据量子力学中的线性叠加原理,构造了由多模相干态|{Zj}〉q与多模虚相干态|{iZj}〉q这两者的线性叠加所组成的第类两态叠加多模叠加态光场|φ6(2)q.利用多模压缩态理论,研究了态|φ6(2)q的广义非线性等阶N次方H压缩特性.结果发现:1)在腔模总数q与压缩阶数N这两者之积取偶数亦即qN=2p的条件下,如果p=2l(l=1,2,3,…,…),则无论各模的初始相位和∑j=1qφj、态间的初始相位差(θpq(R)pq(I))以及各单模相干态光场的平均光子数之和∑j=1qRj2等如何变化,态|φ6(2)q总是恒处于等阶N-H最小测不准态.2)在qN=2p的条件下,如果p=2l+1(l=0,1,2,3,…,…),则当∑j=1qφj、(θpq(R)q(I))、∑j=1qRj2、[(θpq(R)q(I))-∑j=1qRj2]等分别满足一定的量子条件(或者在一些特定的闭区间内连续取值)时,态|φ6(2)q总可呈现出周期性变化的等阶N次方H压缩效应.  相似文献   

12.
W.K. Theumann 《Physica A》1975,80(1):25-45
The order-parameter correlation function G?(q, ξ1) is calculated in the critical region of momentum space q in terms of a second-moment correlation length ξ1 by means of perturbation expansion to order 1/n, for an n-vector system with short-range interactions, in zero field above Tc, for 2 < d < 4. The scaling function of the q dependence is obtained in closed form with a precisely identified cutoff-dependent factor which is the amplitude of the correlation-length dependence of the susceptibility. Both the exponents and the coefficients of the expansion for fixed q as t = (T?Tc)/Tc → 0 are given explicitly and the former are shown to be in accordance with the operator product expansion. The coefficients of order 1/n in the terms associated with a tk(1?α) dependence of the energy density, for integer k ≥ 1, are expected to be explicitly cutoff-dependent and this is verified by the detailed calculations for k = 1. The behaviour for fixed t and q → 0 is shown to be markedly different from the Ornstein-Zernike approximation. Detailed comparison is provided with the scaling function of the t dependence of the correlations appearing in parallel work.  相似文献   

13.
Operator equivalents used in magnetic resonance (electron paramagnetic resonance [EPR], electron-nuclear double resonance, nuclear magnetic resonance, etc.) are considered. The known non-Hermitian tensor operators O ±q (k) (0 ≤ qk) defined by D. Smith and J. H. M. Thornley (Proc. Phys. Soc. 89, 779–781, 1966) after H. A. Buckmaster (Can. J. Phys. 40, 1670–1677, 1962) are expressed in terms of Hermitian cosine and sine operators O kq c and O kq s. These new normalized operators are related to the nonnormalized extended Stevens operators O k q and O k q Ω k q defined by C. Rudowicz (J. Phys. C.: Solid State Phys. 18, 1415–1430, 1985), which are commonly used in EPR of transition ions. The relations between O kq c,s and some other normalized operators occurring in the literature are also given. New crystal-field or spin Hamiltonian parameters B kq c and B kq s associated with the corresponding operators O kq c and O kq s are discussed.  相似文献   

14.
本文根据量子力学中的线性叠加原理,构造了由多模(即q模)相干态的相反态|{-Zj}〉q及多模虚相干态的相反态|{-iZj}〉q这两者的线性叠加所组成的一种新型的两态叠加多模叠加态光场|ψmsc(2)q.利用新近建立的多模辐射场的广义非线性等阶高阶压缩理论,研究了态|ψmsc(2)q的广义非线性等阶N次方Y压缩特性.结果发现,1)当压缩阶数N=2P且P=2m(m=1,2,3,…,…)时,态|ψmsc(2)q恒处于N-Y最小测不准态;2)当N=2P且P=2m’+1(m’=0,1,2,…,…)时,如果各模的初始相位φj、态间的初始相位差与各单模相干态光场的平均光子数之和∑j=1qRj2即[(θpq(R)nq(I))-∑j=1qRj2]满足一定的量子化条件,态|ψmsc(2)q可呈现周期性变化的、任意阶的等阶N次方Y压缩效应;3)当N为奇数时,态|ψmsc(2)q在一定条件下恒处于N-Y测不准态;4)态|ψmsc(2)q与文献21中的态|ψ(2)q出现部分压缩简并现象,从而更进一步表明压缩简并现象的存在是有某种客观内在联系的.  相似文献   

15.
第Ⅴ类两态叠加多模叠加态光场的等阶N次方H压缩特性研究   总被引:39,自引:23,他引:16  
杨志勇  董庆彦  侯瑶  薛红  侯洵 《光子学报》2001,30(7):769-779
本文构造了由多模真空态|{Oj}〉q和多模虚相干态的相反态|{-iZj}〉q这两者的线性叠加所组成的第Ⅴ类两态叠加多模叠加态光场ψ5(2)q,利用多模压缩态理论详细研究了态 ψ5(2)q的广义非线性等阶N次方H压缩特性.结果发现:1)态ψ5(2)q是一种典型的多模非经典光场;无论腔模总数q与压缩阶数N这两者之积q·N取奇还是取偶,只要各模的初始相位之和 、态间的初始相位之差(θnq(I)-θoq(o))等满足一定的量子化条件,态ψ5(2)q总可分别呈现出周期性变化的、任意的奇数模-奇数阶、奇数模-偶数阶、偶数模-偶数阶和偶数模-奇数阶这四种不同形式的等阶N次方H压缩效应.2)上述四种不同形式的等阶N次方H压缩效应,其态间压缩条件完全相同,但模间压缩条件完全不同,结果使其压缩幅度、压缩结果和压缩特性等各不相同.3)无论q·N取奇还是取偶,态ψ5(2)q的第一和第二这两个正交分量的等阶N次方H压缩效应总是呈现周期性的互补关系.  相似文献   

16.
LetΓ=Γ ±,z be one of theN 2-dimensional bicovariant first order differential calculi for the quantum groups GL q (N), SL q (N), SO q (N), or Sp q (N), whereq is a transcendental complex number andz is a regular parameter. It is shown that the de Rham cohomology of Woronowicz’s external algebraΓ ^ coincides with the de Rham cohomologies of its leftinvariant, its right-invariant and its biinvariant subcomplexes. In the cases GL q (N) and SL q (N) the cohomology ring is isomorphic to the biinvariant external algebraΓ inv ^ and to the vector space of harmonic forms. We prove a Hodge decomposition theorem in these cases. The main technical tool is the spectral decomposition of the quantum Laplace-Beltrami operator. It is also applicable for quantum Euclidean spheres. The eigenvalues of the Laplace-Beltrami operator in cases of the general linear quantum group, the orthogonal quantum group, and the quantum Euclidean spheres are given.  相似文献   

17.
赵玲慧  杨志勇  侯瑶  张振杰  侯洵 《光子学报》2000,29(4):293-307,316
本文根据量子力学中的线性叠加原理,构造了由多模(即 q模)相干态的相反态 | {-Zj}〉q及多模虚相干态的相反态 | {-iZj}〉q 这两者的线性叠加所组成的一种新型的两态叠加多模叠加态光场 | ψmsc(2)q 利用新近建立的多模压缩态理论,详细研究了态 | ψmsc(2)q 的广义非线性等阶N次方H压缩特性 结果发现:1)当压缩阶数N与腔模总数q这两者之积为偶数,亦即当q·N =2pp =2m(m =1,2,3,…,…)时,态 | ψmsc(2)q恒处于等阶N-H最小测不准态;2)当q·N =2pp =2m′+ 1(m′ =0,1,2,3,…,…)时,如果各模的初始相位之和 、态间的初始相位差(θnq(I)nq(R))、各多模相干态光场的总的平均光子数 以及 [(θnq(I)nq(R))+ ]等满足一定的量子化条件时,态 | ψmsc(2)q 总可呈现出周期性变化的、任意阶的等阶N次方H压缩效应;3)当压缩阶数N与腔模总数 q这两者之积为奇数时,亦即当 q·N =2p + 1时,无论 p =2m(m =0,1,2,3,…,…)还是 p =2m′ + 1(m′ =0,1,2,3,…,…),只要各模初始相位之和 满足一定的量子化条件,则当两态叠加几率幅满足rnq(R) =rnq(I) 时,态 | ψmsc(2)q 就恒处于N-H测不准态  相似文献   

18.
侯洵  杨志勇 《光子学报》2000,29(5):385-395
本文根据量子力学中的线性叠加原理,分别构造了由多模(即q模)相干态|{Zj}>q与多模真空态|{0j}>q以及由多模相干态的相反态|{-Zj}>q与多模真空态|{0j}>q等的线性叠加所组成的第及第类两态叠加多模叠加态光场|ψ+,3(2)>q和|ψ-,4(2)>q.利用新近建立的多模压缩态理论,首次对态|ψ+,3(2)>q及态|ψ-,4(2)>q的广义非线性等阶N次方Y压缩和等阶N次方H压缩特性进行了详细研究.结果发现:1)态|ψ+,3(2)>q及态|ψ-,4(2)>q是两种典型的多模非经典光场,当各模的初始相位φj(j=1,2,3,…,q)或者各模的初始相位和 =φj以及态间的初始相位差(θ±(R)(0)±)等分别满足一些特定的量子化条件时,态|ψ+,3(2)>q及态|ψ-,4(2)>q均可呈现出周期性变化的、任意阶的等阶N次方Y压缩效应和等阶N次方H压缩效应;2)当组成态|ψ+,3(2)>q及态|ψ-,4(2)>q的各对应复几率幅不相等亦即C+(R)≠C-(R)和C+(0)≠C-(0)时,态|ψ+,3(2)>q及态|ψ-,4(2)>q这两者的压缩条件和压缩特征虽然相同,但其压缩幅度(即压缩程度和压缩深度)却不相等,这种现象称为“相似压缩”;3)当组成态|ψ+,3(2)>q及态|ψ-,4(2)>q的各对应复几率幅相等亦即C+(R)=C-(R)和C+(0)=C-(0)时,态|ψ+,3(2)>q及态|ψ-,4(2)>q这两种截然不同的多模叠加态光场不仅具有完全相同的压缩条件和压缩特征,而且还具有完全相等的压缩幅度,这种现象就称为“压缩简并”.  相似文献   

19.
A quantum state can be understood in a loose sense as a map that assigns a value to every observable. Formalizing this characterization of states in terms of generalized probability distributions on the set of effects, we obtain a simple proof of the result, analogous to Gleason's theorem, that any quantum state is given by a density operator. As a corollary we obtain a von Neumann-type argument against noncontextual hidden variables. It follows that on an individual interpretation of quantum mechanics the values of effects are appropriately understood as propensities.  相似文献   

20.
An approach to formulating the Hellmann–Feynman theorem within the “second choice” formalism of non-extensive statistical mechanics is considered. For the state of thermal equilibrium, we derive a relation of Hellmann–Feynman type between the derivative of the non-extensive free energy with respect to the external parameter and the quantum statistical qq-average of the derivative of the Hamilton operator. We also give a proper extension for an arbitrary observable commuting with the Hamiltonian. Some reasons for the usefulness of new formulas are discussed.  相似文献   

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