What do you mean by metastable state?
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 represents a metastable system?
These are solutions which contain more dissolved solute than is required to form a saturated solution at the same temperature. Supersaturated solutions are, theoretically, unstable but they can be obtained and kept in some cases, they are said to be metastable.
What is the difference between stable and metastable?
The key difference between stable and metastable is that the term stable refers to the state of a material being truly unchanging whereas the term metastable refers to the state of a material where a change cannot be observed because the changing is too slow to be observed.
What does metastable mean in engineering?
Metastable is a term used to refer to a close degree to normal stability ranges or values for any given measurable property of a material, varying slightly to a more unstable level due to the absence of certain chemical, physical or energy conditions. Metastability can be used to describe pitting corrosion.
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.
Why is the metastable state important?
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…
What is a metastable isotope?
Metastable” describes nuclei whose excited states have half-lives 100 to 1000 times longer than the half-lives of the excited nuclear states that decay with a “prompt” half life (ordinarily on the order of 10−12 seconds). The term “metastable” is usually restricted to isomers with half-lives of 10−9 seconds or longer.
What is a metastable protein?
Metastable state of protein is a kinetically trapped structure that has a local free energy minimum, and it is separated from the global free energy minimum conformation by an energy barrier (Figure 1).
What is a metastable material?
Metastable materials, or materials that transform to another state over a long period of time, are ubiquitous in both nature and technology and often have superior properties. Chocolate, for example, is metastable, with a lower melting point and better texture than stable chocolate.
How metastable state is achieved?
Metastable Meaning The population inversion is achieved by optical pumping, i.e., with the help of a continuous supply of energy to the atoms in the lower energy levels and hence they will get excited to the higher energy levels.
What is metastable state?
Metastable state is an excited state of an atom or other system with a longer lifetime than the other excited states. However, it has a shorter lifetime than the stable ground state. Atoms in the metastable state remain excited for a considerable time in the order of 10 -6 to 10 -3.
Is metastable state a temporary energy trap?
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 quantummechanical terms, transitions from metastable states are “forbidden” and are much less probable than the “allowed” transitions from other excited states.
What is a metastable state of finite lifetime?
During a metastable state of finite lifetime, all state-describing parameters reach and hold stationary values. In isolation: the state of least energy is the only one the system will inhabit for an indefinite length of time, until more external energy is added to the system (unique “absolutely stable” state);
What is the metastable state of a laser?
laser: Energy levels and stimulated emissions. …unusually long lifetime, called a metastable state. The metastable state is important because it traps and holds the excitation energy, building up a population inversion that can be further stimulated to emit radiation, dropping the species back to the ground state.