[Pw_forum] a question on 4-phonons interactions

[L.F.Huang (黄良锋)]

Dear Prof. Baroni:
  According to the linear response theory and 2n+1 theorem
(Rev.Mod.Phys.73,515),
it seems that PWSCF can not calculate 4-phonons interactions. But in effect,
the process of 4-phonons interactions is as important as 3-phonons
interactions.
Then my question is:
  Is there any approach to calculate the anharmonicity of some vibration
  modes including 4-phonons interactions ?

  Thank you for your time to read my message!

Best Wishes!
                                         Yours Sincerely
                                            L.F.Huang



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L.F.Huang(黄良锋) lfhuang at theory.issp.ac.cn
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      Instutue of Solid State Physics,the Chinese Academy of Sciences,
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