It is notable that the events observed at this scale are truly stochastic-that is, they are the result of random molecular collision and conformation changes.
12.
Local thermodynamic equilibrium in a gas means that molecular collisions far outweigh light emission and absorption in determining the distributions of states of molecular excitation.
13.
Where \ nu is the molecular collision frequency and f _ 0 is the local Maxwellian distribution function given the gas temperature at this point in space.
14.
Averaged across the entire sample, molecular collisions can be regarded as essentially elastic as long as Planck's law forbids black-body photons to carry away energy from the system.
15.
The stuff about molecular collisions has to do with gases that are intermixing, where buoyancy, as the balloon effect is described as, has little effect on a microscopic scale.
16.
When there is enough matter in a region to allow molecular collisions to occur very much more often than creation or annihilation of photons, for radiation one speaks of local thermodynamic equilibrium.
17.
The temperatures are typically 100-150�C lower than they are in a similar MOCVD or MOVPE . There is also no boundary layer ( such as the one in MOCVD ) and molecular collisions are minimal due to the low pressure.
18.
The construction in Perugia in the Seventies of an original experimental apparatus, where coupling the technique of crossed atomic and molecular beams with the spectroscopic emission detection has led to the discovery of phenomena of polarization and interference in atomic and molecular collisions.
19.
These conditions are unfulfilled, for example, in very rarefied gases, in which molecular collisions are infrequent; and in the boundary layers of a star, where radiation is passing energy to space; and for interacting fermions at very low temperature, where dissipative processes become ineffective.
20.
Continuous movement and molecular collisions visualised as being like bouncing balls blown by air as used in a lottery can then lead on to showing the possibilities of many Boltzmann distributions and continually changing " distribution of the instant ", and on to the idea that when the system changes, dynamic molecules will have a greater number of accessible microstates.
