As for the non-thermal plasma, the rotational temperature is commonly believed to be close to the translational temperature. But is there any non-thermal plasma with much higher rotational temperature? Furthermore, I am very curious that whether the rotational temperatures of different radicals in the plasma are quite different. Hope to find some related literature and studies.
Thank you!
Hello
in non-thermal plasmas R-T relaxation time is shorter than V-T, therefore usually a non-thermal plasma has two different temperatures, translational and vibrational. A high rotatonal temperature has the short lifetime against the common time intervals in plasma, meanwhile rotatonal energy levels are close together and excitation to very high energies for this channel is difficult .usually rotational temperature is equal to translational temperature with good approximation. For more information you can see "plasma chemistry " by freedman.
Best regards
Both Rotational and vibrational temperature depend on operating conditions. Typically in low-pressure (few mTorr) magnetron discharges the rotational temperature is some what higher and comaparable with the vibrational temperature.
You may go through this link to have more idea.
http://iopscience.iop.org/article/10.1088/0022-3727/40/4/016/pdf
Good luck.