A quantum-statistical-mechanical theory of equilibrium states was developed to present a simple realistic model of DNA denaturation. Applying the Feynman free energy minimum principle approach to the free energy of an anharmonic oscillator representing an interchain H-bond between DNA strands a simple formula for its melting temperature was derived. Experimental Raman and IR vibrational data we...

We report model calculations on DNA single strands which describe the equilibrium dynamics and kinetics of hairpin formation and melting. Modeling is at the level of single bases. Strand rigidity is described in terms of simple polymer models; alternative calculations performed using the freely rotating chain and the discrete Kratky-Porod models are reported. Stem formation is modeled according...

In a beautiful experiment Williamson, Mourou, and Li' have measured directly the time it takes for the solid-liquid transition of a free-standing aluminum film. This was done by a direct measurement of the disappearence of electron diffraction patterns after the application of a short laser pulse. The results are interpreted' as due to an expansion of a critical nucleus of the melt throughout t...

Many factors that change the temperature position and interval of the DNA helix-coil transition often also alter the shape of multi-peak differential melting curves (DMCs). For DNAs with a multi-peak DMC, there is no agreement on the most useful definition for the melting temperature, Tm, and temperature melting width, ΔT, of the entire DNA transition. Changes in Tm and ΔT can reflect unstable ...

Bulk metallic glass-forming Pd40Ni10Cu30P20 has been investigated in its equilibrium liquid by quasielastic neutron scattering. The quasielastic signal exhibits a structural relaxation as known from nonmetallic viscous liquids. Even well above the melting point, the structural relaxation is nonexponential and obeys a universal time-temperature superposition. From the mean relaxation times avera...

Using the emulsion method, we measured the homogeneous nucleation temperature depression, DeltaT(f,hom), and equilibrium melting points depression, DeltaT(m), of various aqueous solutions and then calculated lambda for each solute using the linear relationship DeltaT(f,hom) = lambdaDeltaT(m). We defined lambda as the solute-specific supercooling capacity and examined its correlation with some k...

Using ab initio and parametrized techniques, we determine the equilibrium structure of an ordered “bundle” of (10,10) carbon nanotubes. Because of small intertube interaction and lattice frustration, we predict a very soft libration mode to occur at n ø 12 cm21. This mode is predicted to disappear above the orientational melting temperature which marks the onset of free tube rotations about the...

In this second installment of a series that aims to investigate the dynamic interaction between the composition and abundance of the solid mantle and its melt products, the classic interpretation of fractional melting is extended to account for the dynamic nature of the process. A multiphase numerical flow model is coupled with the program AlphaMELTS, which provides at the moment possibly the m...

The DINAMelt web server simulates the melting of one or two single-stranded nucleic acids in solution. The goal is to predict not just a melting temperature for a hybridized pair of nucleic acids, but entire equilibrium melting profiles as a function of temperature. The two molecules are not required to be complementary, nor must the two strand concentrations be equal. Competition among differe...

The threshold laser fluence for the onset of surface melting is calculated for Ni films of different thicknesses and for a bulk Ni target using a combined atomistic-continuum computational model. The model combines the classical molecular dynamics (MD) method for simulation of non-equilibrium processes of lattice superheating and fast phase transformations with a continuum description of the la...