Which phenomenon is described by the term 'quantum tunneling'?

In spectroscopy, what does the term 'Stark effect' refer to? In spectroscopy, what is the significance of the Franck-Condon principle? In the context of phase transitions, what does the term 'latent heat' refer to? In the context of quantum mechanics, what does the Pauli exclusion principle state? Which type of chemical bond involves the sharing of electron pairs between atoms? Which equation relates the Gibbs free energy to the equilibrium constant? Which law describes the relationship between the intensity of light absorbed and the concentration of the absorbing species? What is the main purpose of the Schr?dinger equation in quantum mechanics? What is the primary purpose of a catalyst in a chemical reaction? Which concept explains the deviation of real gases from ideal behavior? What is the primary factor that determines the rate of a chemical reaction? Which concept in thermodynamics is described by the Gibbs phase rule? What is the main principle behind the 'Tyndall effect' in colloidal chemistry? Which technique is used to study the energy levels of electrons in atoms and molecules? What is the primary use of the Arrhenius equation in chemical kinetics? Which thermodynamic quantity is maximized at equilibrium for a closed system? Which term describes the equilibrium constant of a reaction in which all reactants and products are in the same phase? What is the role of a Maxwell relation in thermodynamics? Which type of molecular vibration is active in IR spectroscopy? In electrochemistry, what does the term 'standard electrode potential' refer to? What does the term 'spin-orbit coupling' describe in atomic structure? Which principle explains the emission and absorption spectra of atoms? What is the significance of the Bohr radius in atomic physics? What is the principle behind the Boltzmann distribution in statistical mechanics? What is the concept of 'chemical potential' in thermodynamics? What is the significance of the partition function in statistical mechanics? What is the fundamental principle behind the Heisenberg Uncertainty Principle? What is the key concept behind the Debye-H?ckel theory in electrochemistry? What is the principle of 'Le Chatelier's Principle' in chemical equilibrium? What is the concept of 'enthalpy of formation'? In solid-state chemistry, what does the term 'band gap' refer to? What is the main outcome of the Born-Oppenheimer approximation in molecular quantum mechanics? In the context of reaction mechanisms, what does the term 'rate-determining step' refer to? Which term describes the change in Gibbs free energy for a reaction at constant temperature and pressure? Which theory explains the shapes of molecular orbitals formed from atomic orbitals? What is the primary focus of the Langmuir adsorption isotherm? What is the principle of microscopic reversibility in chemical kinetics? What is the significance of the 'Z' parameter in crystallography? In surface chemistry, what does the term 'chemisorption' imply? In thermodynamics, what does the Helmholtz free energy represent? In quantum chemistry, what does the term 'degenerate orbitals' refer to? Which phenomenon is described by the term 'quantum tunneling'?