Non-Adiabatic versus excited state

[greisen]

Hi,

I am reading about protons and their transfer mechanisms and often the words nonadiabatic and excited state are used in a way which confuses me.

If I have a proton in a higher vibrating state (E1) I would called that an excited state for the proton - is this also a non-adiabatic state for the proton?

Any help or advise appreciated.

Thanks in advance

Best

 

[chemisttree]

I would think that for larger masses like the proton, non-adiabatic processes would be very important (relative to electronic excited states). In NMR, these non-adiabatic processes occur between the excited magnetic state of the proton and nearby (physically nearby) lattice. The relaxation of the excited state magnetizaton occurs through interaction with the solvent and other analyte molecules (the 'lattice') and through nearby (both physically and electronically) spin systems. These energy transfer mechanisms would be defined as non-adiabatic since they are intermolecular transfers of energy.

A good definition of 'non-adiabatic' and 'adiabatic' for excited state systems can be found here:

http://www.worldscibooks.com/phy_etextbook/4783/4783_chap1.pdf

 

[Blueshift5]

regards,

A non-adiabatic state refers to a state in which the energy of a system is changing rapidly, typically due to some external force or interaction. An excited state, on the other hand, refers to a state in which the energy of a system is higher than its ground state. These two terms are often used in the context of proton transfer mechanisms, as you mentioned.

In the case of a proton in a higher vibrating state (E1), this can be considered an excited state for the proton since it has a higher energy compared to its ground state. However, whether it is also a non-adiabatic state would depend on the rate at which the energy is changing. If the energy is changing rapidly, then it could be considered non-adiabatic.

It is important to note that these are not mutually exclusive terms and a system can be both in an excited state and a non-adiabatic state at the same time. Additionally, the behavior of a system in an excited state can be affected by external forces, leading to non-adiabatic behavior.

I hope this helps clarify the difference between non-adiabatic and excited states in the context of proton transfer. Keep in mind that these terms can have slightly different meanings in other scientific fields, so it is always important to consider the specific context in which they are being used.