Why does vibrational relaxation occur.

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In summary, the conversation discusses the interaction between a photon of light and a molecule of water, resulting in the molecule vibrating in a symmetric stretch. This excited state eventually decays into other modes of the system, such as bend, rotations, or translations, due to the coupling with the surrounding bath. The speaker is seeking a physical understanding of this decay and references the Bixon Jortner model for further study.
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DinosaurChemi
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Take the case of a bath/system of water. A photon of light is allowed to interact with one molecule of water giving it let's say 3200 1/cm exciting a "symmetric" stretch or some normal mode of the system similar to a symmetric stretch. The molecule will begin to vibrate but as time goes on this state which is excited will decay into either the bend, rotations or translations of the bath (i.e. the bath being everything but the excited stretch). Why does the relaxation occurs. I understand that due to coupling of the system (excited mode) with the bath I will be faced with a excitation of a linear combination of eigenstate for my system and not a true eigenstate since i have brought all these water molecules together. Is there even a way to excite a true eigenstate in such a situation? I guess I am looking for a physical understanding of the decay.
 
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What is vibrational relaxation?

Vibrational relaxation is the process by which a molecule in an excited vibrational state transfers its excess energy to the surrounding environment, usually through collisions with other molecules or through radiation. This results in the molecule returning to its ground state.

Why does vibrational relaxation occur?

Vibrational relaxation occurs in order to maintain the overall energy balance of a system. When a molecule is excited to a higher vibrational state, it is in an unstable state and will naturally want to return to its more stable ground state. The excess energy is therefore transferred to the surrounding environment, leading to vibrational relaxation.

What factors affect the rate of vibrational relaxation?

The rate of vibrational relaxation can be affected by several factors, including temperature, pressure, collision frequency, and the nature of the surrounding environment. Higher temperatures and pressures, as well as more frequent collisions, can enhance the rate of vibrational relaxation.

How is vibrational relaxation important in chemistry and physics?

Vibrational relaxation is a fundamental process in chemistry and physics, as it plays a crucial role in many chemical and physical processes. It is important in understanding the behavior of molecules in gases, liquids, and solids, and has applications in fields such as spectroscopy, thermodynamics, and atmospheric science.

Can vibrational relaxation be controlled or manipulated?

Yes, vibrational relaxation can be controlled and manipulated through various methods, such as using lasers to selectively excite specific vibrational states or changing the surrounding conditions (e.g. temperature or pressure) to alter the rate of relaxation. This allows for the study and manipulation of molecular systems and can have practical applications in fields such as energy conversion and chemical reactions.

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