Polarisable

Polarisable refers to a property of certain objects or systems, particularly in physics and chemistry, where their electron distribution can be distorted by an external electric field. This distortion causes the object to develop an induced dipole moment. Essentially, the positive and negative charges within the object are shifted relative to each other, even if the object was not originally polar.

The degree to which a substance is polarisable is known as its polarisability. It is a measure of how easily the electron cloud can be deformed. Factors influencing polarisability include the number of electrons in the atom or molecule and their spatial distribution. Larger atoms and molecules with more diffuse electron clouds are generally more polarisable than smaller, more compact ones.

In chemistry, polarisability plays a role in intermolecular forces, specifically London dispersion forces, which arise from temporary, induced dipoles. It is also relevant in understanding the behaviour of molecules in the presence of electric fields, such as in dielectrics. In physics, the concept is applied in the study of electromagnetic waves interacting with matter and in the modelling of atomic and molecular responses.

The opposite of polarisable would be a non-polarisable object, where the electron distribution is rigid and not easily distorted by an electric field. Understanding polarisability is crucial for accurately predicting chemical reactivity, physical properties, and the behaviour of materials under various conditions.