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Morse Potential (morse + potential)

Distribution by Scientific Domains

Chemistry	58%
Physics and Astronomy	33%

Selected Abstracts

Application of the anharmonic coherent states to the vibronic interaction

FORTSCHRITTE DER PHYSIK/PROGRESS OF PHYSICS, Issue 2-3 2003
C.N. Avram
We calculated the vibronic reduction factor (Ham factor) for the physical system (molecules, crystals) with octahedral symmetry. The vibrations of the nuclei of the systems are described by the anharmonic states of the Morse potential and also by the anharmonic coherent states of the same potential. The linear vibronic coupling of these vibration states with the electronic states of the system are considered. [source]

Laser control of photodissociation process in diatomic molecule

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 14 2009
A. Tawada
Abstract In this work, we first aim to realize the complete laser-induced photodissociation of the OH molecule, and then intend to control the wavepacket generated on the continuum state, i.e., to achieve the laser control of the above-threshold dissociation (ATD) spectrum. To numerically solve the Schrödinger equation, we adopt the split operator method (SOM), which conserves the norm of the state vector, and can treat both discrete and continuum states simultaneously and correctly. This photodissociation process induced by the multiphoton absorption involves the ATD spectrum due to the continuum-continuum transition by the intense electric field. First, we investigate the detailed mechanism of the complete photodissociation with the one-color laser pulse by changing the laser parameters. Then, we investigate the control of the ATD spectrum by using the two-color laser field, where we focus on the role of the relative phase and position of two laser pulses. To analyze the population of both discrete and continuum states involved in the resultant wavepacket, we show the effective method by means of the quasicontinuum state on the Morse potential obtained by numerically diagonalizing the Fourier grid Hamiltonian (FGH). © 2009 Wiley Periodicals, Inc. Int J Quantum Chem, 2009 [source]

Morse potential eigen-energies through the asymptotic iteration method

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 10 2007
O. M. Al-DossaryArticle first published online: 16 MAR 200
Abstract The eigen-energies of the rotating Morse potential based on the original Pekeris approximation are obtained by means of the asymptotic iteration method. This approach is applied to several diatomic molecules, and it is shown that the numerical results for the eigen-energies are all in excellent agreement with the ones obtained before. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007 [source]

Comparative analysis of ArnCl2 (2 , n , 30) clusters taking into account molecular relaxation effects

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 13 2006
G. G. Ferreira
Abstract Cluster structures are discussed in a nonrigid analysis, using a modified minima search method based on stochastic processes and classical dynamics simulations. The relaxation process is taken into account considering the internal motion of the Cl2 molecule. Cluster structures are compared with previous works in which the Cl2 molecule is assumed to be rigid. The interactions are modeled using pair potentials: the Aziz and Lennard,Jones potentials for the ArAr interaction, a Morse potential for the ClCl interaction, and a fully spherical/anisotropic Morse,Spline,van der Waals (MSV) potential for the ArCl interaction. As expected, all calculated energies are lower than those obtained in a rigid approximation; one reason may be attributed to the nonrigid contributions of the internal motion of the Cl2 molecule. Finally, the growing processes in molecular clusters are discussed, and it is pointed out that the growing mechanism can be affected due to the nonrigid initial conditions of smaller clusters such as ArnCl2 (n , 4 or 5), which are seeds for higher-order clusters. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [source]

Computation of the eigenvalues of the one-dimensional Schrödinger equation by symplectic methods

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 4 2006
Z. Kalogiratou
Abstract The computation of high-state eigenvalues of the one-dimensional time-independent Schrödinger equation is considered by symplectic integrators. The Schrödinger equation is first transformed into a Hamiltonian canonical equation. Yoshida-type symplectic integrators are used as well as symplectic integrators based on the Magnus expansion. Numerical results are obtained for a wide range of eigenstates of the one-dimensional harmonic oscillator, the doubly anharmonic oscillator, and the Morse potential. The eigenvalues found by the symplectic methods are compared with the eigenvalues produced by Numerov-type methods. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006 [source]

Explicitly correlated SCF study of anharmonic vibrations in (H2O)2

INTERNATIONAL JOURNAL OF QUANTUM CHEMISTRY, Issue 4-5 2002
Donald D. Shillady
Abstract Modeling solvation in high-pressure liquid chromatography (HPLC) requires calculation of anharmonic vibrational frequencies of solvent clusters for a statistical partition function. An efficient computational method that includes electron correlation is highly desirable for large clusters. A modified version of the "soft Coulomb hole" method of Chakravorty and Clementi has recently been implemented in a Gaussian-lobe-orbital (GLO) program (PCLOBE) to include explicit electron,electron correlation in molecules. The soft Coulomb hole is based on a modified form of Coulomb's law: An algorithm has been developed to obtain the parameter "w" from a polynomial in the effective scaling of each primitive Gaussian orbital relative to the best single Gaussian of the H1s orbital. This method yields over 90% of the correlation energy for molecules of low symmetry for which the original formula of Chakravorty and Clementi does not apply. In this work, all the vibrations of the water dimer are treated anharmonically. A quartic perturbation of the harmonic vibrational modes is constrained to be equal to the exact Morse potential eigenvalue based on a three-point fit. This work evaluates the usefulness of fitting a Morse potential to a hydrogen bond vibrational mode and finds it to be slightly better than using MP2 vibrational analysis for this important dimer. A three-point estimate of the depth, De, of a Morse potential leads to a correction formula for anharmonicity in terms of the perturbed harmonic frequency: When scaled by 0.9141, the harmonic Morse method leads to essentially the same results as scaling the BPW91 local density method by 0.9827. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem, 2002 [source]

PRICING EQUITY DERIVATIVES SUBJECT TO BANKRUPTCY

MATHEMATICAL FINANCE, Issue 2 2006
Vadim Linetsky
We solve in closed form a parsimonious extension of the Black,Scholes,Merton model with bankruptcy where the hazard rate of bankruptcy is a negative power of the stock price. Combining a scale change and a measure change, the model dynamics is reduced to a linear stochastic differential equation whose solution is a diffusion process that plays a central role in the pricing of Asian options. The solution is in the form of a spectral expansion associated with the diffusion infinitesimal generator. The latter is closely related to the Schrödinger operator with Morse potential. Pricing formulas for both corporate bonds and stock options are obtained in closed form. Term credit spreads on corporate bonds and implied volatility skews of stock options are closely linked in this model, with parameters of the hazard rate specification controlling both the shape of the term structure of credit spreads and the slope of the implied volatility skew. Our analytical formulas are easy to implement and should prove useful to researchers and practitioners in corporate debt and equity derivatives markets. [source]

Interaction between helium and vacancy in plutonium by embedded atom method

PHYSICA STATUS SOLIDI (B) BASIC SOLID STATE PHYSICS, Issue 8 2008
Bingyun Ao
Abstract The formation energies of small Hen Vm clusters (n and m denote the number of He atoms and vacancy, respectively) in Pu have been calculated with molecular dynamics (MD) simulations using the embedded atom method (EAM) potential, the Morse potential and the Lennard,Jones potential for describing the interactions of Pu,Pu, Pu,He and He,He, respectively. The binding energies of an interstitial He atom, an isolated vacancy and a self-interstitial Pu atom to a Hen Vm cluster are also obtained from the calculated formation energies of the clusters. All the binding energies mainly depend on the He-vacancy ratio (n /m) of clusters rather than the clusters size. With the increase of the n /m ratio, the binding energies of a He atom and a Pu atom to a Hen Vm cluster decrease with the ratio, and the binding energy of a vacancy to a Hen Vm cluster increases. He atoms act as a catalyst for the formation of Hen Vm clusters. (© 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source]

Theoretical study on adsorption and diffusion of N atoms on Cu low-index surface

CHINESE JOURNAL OF CHEMISTRY, Issue 11 2004
Zhao-Yu Diao
Abstract The adsorption and diffusion of N atoms on the three low-index Cu planes were studied using 5-parameter Morse potential (5-MP) method, and the best theory-experiment agreement was obtained. N atom of Cu(100) surface sit on the fourfold hollow site with the vertical height of 0.018 nm closely coplanar with the topmost copper layer, and the four CuN bond lengths are 0.182 nm and the fifth CuN distance is 0.199 nm. For Cu(111) system, the existence of aberrant Cu(100) reconstructed structure is approved at higher coverage, and at low coverage the structure is almost an ideal Cu(111) surface structure. With respect to Cu(110) system, the N atoms are adsorbed at LB and H3 sites, not at SB site. The diffusion passage and diffusion barrier of adsorbed N atoms were also studied. [source]

A force-field description of short-range repulsions for high density alkane molecular dynamics simulations

JOURNAL OF COMPUTATIONAL CHEMISTRY, Issue 16 2004
Joseph M. Hayes
Abstract The use of Buckingham (exp-6) van der Waals potentials in molecular dynamics (MD) simulations can quite successfully reproduce experimental thermodynamic data at low densities. However, they are less successful in producing a description of the repulsive regions of the potential energy surface (PES) that is in accord with the results of high-level ab initio computations. We show that Morse potentials can be parameterized to give excellent fits to both the attractive and repulsive regions of the PES. The best set of alkane van der Waals Morse function parameters reported to date for the description of nonbond repulsive interactions is presented, as determined by comparison with both ab initio and experimental results. C,C, H,H and C,H atom-pair potentials employing parameter sets based on the use of the geometric mean in the fitting procedure are found to be portable from methane to n- butane. Fitting to a combination of methane dimer interaction energies and forces from ab initio calculations yields parameter sets whose performance is superior to those determined from the interaction energies alone. Used in MD simulations, our newly developed parameter sets predict thermodynamic functions that show better agreement with experiment than those based on parameter sets in common use. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1953,1966, 2004 [source]

Approximate analytical solutions of the pseudospin symmetric Dirac equation for exponential-type potentials

ANNALEN DER PHYSIK, Issue 10-11 2009
A. Arda
Abstract The solvability of The Dirac equation is studied for the exponential-type potentials with the pseudospin symmetry by using the parametric generalization of the Nikiforov,Uvarov method. The energy eigenvalue equation, and the corresponding Dirac spinors for Morse, Hulthen, and q -deformed Rosen,Morse potentials are obtained within the framework of an approximation to the spin-orbit coupling term, so the solutions are given for any value of the spin-orbit quantum number , = 0, or , , 0. [source]