What is metastable state explain?

What is metastable state explain?

metastable state, in physics and chemistry, particular excited state of an atom, nucleus, or other system that has a longer lifetime than the ordinary excited states and that generally has a shorter lifetime than the lowest, often stable, energy state, called the ground state.

What is the role of metastable state?

In a three-level laser, the material is first excited to a short-lived high-energy state that spontaneously drops to a somewhat lower-energy state with an unusually long lifetime, called a metastable state. The metastable state is important because it traps and holds the excitation energy, building up a…

How is a metastable state formed?

In some of these lasers, helium atoms are excited into metastable states by an electric discharge. In collisions with other atoms (e.g. neon in a helium–neon laser), they can then transfer the excitation energy to those atoms. It also occurs that after the laser transition atoms are “stuck” in a metastable state.

What is the meaning of metastable phase?

[¦med·ə′stā·bəl ¦fāz] (physical chemistry) Existence of a substance as either a liquid, solid, or vapor under conditions in which it is normally unstable in that state.

What is metastable state and population inversion?

In this system, the ground state is the lower laser level, and a population inversion is created between this level and a higher-energy metastable state. Most of the atoms or molecules are initially excited to a short-lived high-energy state that is higher than the metastable level.

Why the metastable state has such a long lifetime?

In chemistry and physics, metastability denotes an intermediate energetic state within a dynamical system other than the system’s state of least energy. Higher energy isomers are long lived because they are prevented from rearranging to their preferred ground state by (possibly large) barriers in the potential energy.

What are examples of metastable?

A ball resting in a hollow on a slope is a simple example of metastability. If the ball is only slightly pushed, it will settle back into its hollow, but a stronger push may start the ball rolling down the slope. Bowling pins show similar metastability by either merely wobbling for a moment or tipping over completely.

How does metastable state help in lasing action?

The population of metastable state can exceed the population at a lower level thereby establishing population inversion in a lasing medium. Metastable levels with long lifetimes allow storage of significant amount of energy, and hence they are critical for Q-switched lasers.

What metastable means?

metastable. / (ˌmɛtəˈsteɪbəl) physics / adjective. (of a body or system) having a state of apparent equilibrium although capable of changing to a more stable state. (of an atom, molecule, ion, or atomic nucleus) existing in an excited state with a relatively long lifetime.

What is metastable state in VLSI?

Meta stable state refers to the state in which a digital block/circuit stays in an unstable equilibrium state. That is , the circuit will not be able to settle to a stable 0/1 rather will be between 0/1.

What is the prompt reason behind the existence of metastable state?

The most common reason for metastable states in atoms (or molecules) is due to the metastable state having different spin than the ground state.

Why is a metastable state more stable?

Metastable state, in physics, is the particularlyly excited energy level or higher energy level of an atom, nucleus, or other systems that have a longer lifetime than the ordinary excited states (or the energy levels) and that generally has a shorter lifetime than the lowest, often highly stable, energy state is known …

Which is longer the ground state or the metastable state?

Metastable state. Written By: Metastable state, in physics and chemistry, particular excited state of an atom, nucleus, or other system that has a longer lifetime than the ordinary excited states and that generally has a shorter lifetime than the lowest, often stable, energy state, called the ground state.

How is a metastable state related to an excited state?

A metastable state may thus be considered a kind of temporary energy trap or a somewhat stable intermediate stage of a system the energy of which may be lost in discrete amounts. In quantum mechanical terms, transitions from metastable states are “forbidden” and are much less probable than the “allowed” transitions from other excited states.

Which is the best example of metastability in physics?

A metastable state of weaker bond (1), a transitional ‘saddle’ configuration (2) and a stable state of stronger bond (3). In physics, metastability is a stable state of a dynamical system other than the system’s state of least energy . A ball resting in a hollow on a slope is a simple example of metastability.

How is metastable state related to population inversion?

During metastable state, all the parameters associated with state hold stationary values. A large number of excited atoms are accumulated in the metastable state. The population of metastable state can exceed the population at a lower level thereby establishing population inversion in a lasing medium.