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Dear QE users,</div>
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I use Ph.x to calculate the ZPE and frequency of adsorbed N2 molecules on surface, except the gas the surface is fixed. But the results show that some negative frequency in fixed atom, why?</div>
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The result and input file is shown below:</div>
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<span> Mode symmetry, C_1 (1) point group:<br>
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<div> freq ( 1 - 1) = -1221.6 [cm-1] --> A I+R<br>
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<div> freq ( 2 - 2) = -972.9 [cm-1] --> A I+R<br>
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<div> freq ( 3 - 3) = -772.4 [cm-1] --> A I+R<br>
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<div> freq ( 4 - 4) = -636.6 [cm-1] --> A I+R<br>
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<div> freq ( 5 - 5) = -466.0 [cm-1] --> A I+R<br>
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<div> freq ( 6 - 6) = -266.5 [cm-1] --> A I+R<br>
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<div> freq ( 7 - 7) = -167.5 [cm-1] --> A I+R<br>
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<div> freq ( 8 - 8) = -93.4 [cm-1] --> A I+R<br>
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<div> freq ( 9 - 9) = -54.9 [cm-1] --> A I+R<br>
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<div> freq ( 10 - 10) = -49.0 [cm-1] --> A I+R<br>
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<div> freq ( 11 - 11) = -32.7 [cm-1] --> A I+R<br>
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<div> freq ( 12 - 12) = -25.1 [cm-1] --> A I+R<br>
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<div> freq (196 -196) = 95.3 [cm-1] --> A I+R<br>
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<div> freq (197 -197) = 453.7 [cm-1] --> A I+R<br>
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<div> freq (198 -198) = 504.5 [cm-1] --> A I+R<br>
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<div> freq (199 -199) = 605.5 [cm-1] --> A I+R<br>
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<div> freq (200 -200) = 712.9 [cm-1] --> A I+R<br>
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<div> freq (201 -201) = 1080.1 [cm-1] --> A I+R<br>
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<div> freq (202 -202) = 1179.6 [cm-1] --> A I+R<br>
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<div> freq (203 -203) = 1219.7 [cm-1] --> A I+R<br>
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<div> freq (204 -204) = 1261.5 [cm-1] --> A I+R<br>
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<div> freq (205 -205) = 1563.9 [cm-1] --> A I+R<br>
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<div> freq (206 -206) = 3291.5 [cm-1] --> A I+R<br>
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<span> freq (207 -207) = 3398.0 [cm-1] --> A I+R</span><br>
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<span><br>
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<span><span><br>
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<div>&INPUTPH</div>
<div> prefix='n2',<br>
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<div> tr2_ph = 1d-12,<br>
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<div> ldisp = .true. ,</div>
<div> epsil=.false.,<br>
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<div> trans=.true.,<br>
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<div> nq1 = 1 ,<br>
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<div> nq2 = 1 ,<br>
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<div> nq3 = 1 ,<br>
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<div> nat_todo = 2,<br>
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<div> alpha_mix(1) = 0.07,<br>
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<div> recover = .true. ,<br>
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<div>/<br>
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<div>66 67<br>
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<span></span><br>
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<span>Many thanks</span></div>
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<span><br>
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<span>CLarence</span></div>
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<span>CIty University of Hong Kong</span></div>
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