Imaginary Harmonic Modes

These flashcards cover key concepts from the lecture on imaginary harmonic modes and their implications in chemistry.

Boltzmann distribution

A statistical distribution that describes the distribution of energy levels among particles in a thermodynamic system.

Imaginary harmonic modes

Modes corresponding to negative eigenvalues in the dynamical matrix indicating local maxima on the potential energy surface.

Potential-energy surface (PES)

A multidimensional surface that represents the potential energy of a system as a function of its molecular structure.

Transition-state theory

A theory that describes the transition states of chemical reactions, which are at maximum potential energy.

Eyring equation

An equation that relates the rate of a chemical reaction to the temperature and activation energy via transition-state theory.

Dynamical stability

The stability of a system's structure based on its vibrational modes and whether they correspond to negative eigenvalues.

Eigenvalue

A scalar that indicates how much a particular transformation (like a vibration mode) changes in a dynamic system.

Negative eigenvalues

Indicates a system is dynamically unstable, suggesting the presence of imaginary modes.

Phase transitions

Changes in the state of matter, such as solid to liquid, characterized by specific energy changes.

Supramolecular materials

Materials formed by the association of two or more chemical species through non-covalent bonds.