Physics at Atomic Scale
In this section of our web site we will be covering various phenomena at atomic scale ranging from fundamental laws of physics to industrial applications. Atomic scale electronics, which is known as molecular electronics is covered in a separate section.
Atoms have heavy nuclei, which are made of positively charged protons and neutrons, and light negatively charged electrons. High energy particles, such photons (photon is a particle as well!), ions or electrons can kick off electrons from atoms, turning them into ions. In absence of such disturbance (and if quantum effects can be ignored) atoms can be considered as classical particles, free or bound to other atoms by chemical bonds and their interactions can be described by classical molecular mechanics. The very large number of atoms and molecules (macroscopic systems) are governed by laws of thermodynamics and statistical mechanics.
The nano scale systems (approximately from 1 to 100 nm) often show very pecular behavior which is not easy to predict because the number of atoms in such systems is often too large for an adequate quantum mechanical description (but some collective phenomena are already present in such systems) but too small for application of laws of statistical mechanics and thermodynamics (very large fluctuations).
For example, mechanical properties of nano systems require an accurate estimate of surface energy, since the number of surface atoms in nano systems is comparable to the number of the atoms in the bulk. The electric phenomena in nano systems are often influenced by, so called, Coulomb blockade, which results from quantum tunneling and electron trapping phenomena.