Philip M. Morse

Bio: Philip M. Morse is an academic researcher from Massachusetts Institute of Technology. The author has contributed to research in topics: Electron & Absorption (acoustics). The author has an hindex of 37, co-authored 117 publications receiving 25198 citations. Previous affiliations of Philip M. Morse include Princeton University.

Diatomic Molecules According to the Wave Mechanics. II. Vibrational Levels

Abstract: An exact solution is obtained for the Schroedinger equation representing the motions of the nuclei in a diatomic molecule, when the potential energy function is assumed to be of a form similar to those required by Heitler and London and others. The allowed vibrational energy levels are found to be given by the formula $E(n)={E}_{e}+h{\ensuremath{\omega}}_{0}(n+\frac{1}{2})\ensuremath{-}h{\ensuremath{\omega}}_{0}x{(n+\frac{1}{2})}^{2}$, which is known to express the experimental values quite accurately. The empirical law relating the normal molecular separation ${r}_{0}$ and the classical vibration frequency ${\ensuremath{\omega}}_{0}$ is shown to be ${{r}_{0}}^{3}{\ensuremath{\omega}}_{0}=K$ to within a probable error of 4 percent, where $K$ is the same constant for all diatomic molecules and for all electronic levels. By means of this law, and by means of the solution above, the experimental data for many of the electronic levels of various molecules are analyzed and a table of constants is obtained from which the potential energy curves can be plotted. The changes in the above mentioned vibrational levels due to molecular rotation are found to agree with the Kratzer formula to the first approximation.

Vibration and sound

Abstract: CHAPTER II THE SIMPLE OSCILLATOR 3. Free Oscillations The General Solution. Initial Conditions. Energy of Vibration 4. Damped Oscillations The General Solution. Energy Relations 5. Forced Oscillations The General Solution. Transient and Steady State. Impedance and Phase Angle. Energy Relations. Electromechanical Driving Force. Motional Impedance. Piezoelectric Crystals. 6. Response to Transient Forces Representation by Contour Integrals. Transients in a Simple System. Complex Frequencies. Calculating the Transients. Examples of the Method. The Unit Function. General Transient. Some Generalizations. Laplace Transfoms. 7. Coupled Oscillations The General Equation. Simple Harmonic Motion. Normal Modes of Vibration. Energy Relations. The Case of Small Coupling. The Case of Resonance. Transfer of Energy. Forced Vibrations. Resonance and Normal Modes. Transient Response. Problems

CHARMM: the biomolecular simulation program.

Abstract: CHARMM (Chemistry at HARvard Molecular Mechanics) is a highly versatile and widely used molecu- lar simulation program. It has been developed over the last three decades with a primary focus on molecules of bio- logical interest, including proteins, peptides, lipids, nucleic acids, carbohydrates, and small molecule ligands, as they occur in solution, crystals, and membrane environments. For the study of such systems, the program provides a large suite of computational tools that include numerous conformational and path sampling methods, free energy estima- tors, molecular minimization, dynamics, and analysis techniques, and model-building capabilities. The CHARMM program is applicable to problems involving a much broader class of many-particle systems. Calculations with CHARMM can be performed using a number of different energy functions and models, from mixed quantum mechanical-molecular mechanical force fields, to all-atom classical potential energy functions with explicit solvent and various boundary conditions, to implicit solvent and membrane models. The program has been ported to numer- ous platforms in both serial and parallel architectures. This article provides an overview of the program as it exists today with an emphasis on developments since the publication of the original CHARMM article in 1983.

Snakes, shapes, and gradient vector flow

Abstract: Snakes, or active contours, are used extensively in computer vision and image processing applications, particularly to locate object boundaries. Problems associated with initialization and poor convergence to boundary concavities, however, have limited their utility. This paper presents a new external force for active contours, largely solving both problems. This external force, which we call gradient vector flow (GVF), is computed as a diffusion of the gradient vectors of a gray-level or binary edge map derived from the image. It differs fundamentally from traditional snake external forces in that it cannot be written as the negative gradient of a potential function, and the corresponding snake is formulated directly from a force balance condition rather than a variational formulation. Using several two-dimensional (2-D) examples and one three-dimensional (3-D) example, we show that GVF has a large capture range and is able to move snakes into boundary concavities.