"We have 144 normal modes, corresponding to thenumber of degrees of freedom of 4 CH3NH3PbI3units in ourunit cell"
Ref:1. https://pubs.acs.org/doi/epdf/10.1021/acs.jpcc.5b07432----------------------------------------------------2.https://scholar.google.com/citations?view_op=view_citation&hl=en&user=4Ncn-GUAAAAJ&sortby=pubdate&citation_for_view=4Ncn-GUAAAAJ:9yKSN-GCB0IC 在 2023年10月24日 星期二 下午11:25:48 [GMT+8]， [email protected]<[email protected]> 寫道： Dear QE users:I have a naive question of how to determine the number of unit cell to I need to calculate vibrational frequencies.(at Gamma point) In the below 2 paper, I saw authors choosing 4 unit cells of perovskite (MAPbI3) for phonon calculation. However, I do not know what number of unit cell should I use? Is their any way to determine it ? Sincerely, National Yang Ming Chiao Tung University HY Lu Ref:1. https://pubs.acs.org/doi/epdf/10.1021/acs.jpcc.5b074322.https://scholar.google.com/citations?view_op=view_citation&hl=en&user=4Ncn-GUAAAAJ&sortby=pubdate&citation_for_view=4Ncn-GUAAAAJ:9yKSN-GCB0IC
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