<html>
<head>
<style><!--
.hmmessage P
{
margin:0px;
padding:0px
}
body.hmmessage
{
font-size: 10pt;
font-family:Tahoma
}
--></style></head>
<body class='hmmessage'><div dir='ltr'>
Thanks for the information, Prof. Giannozzi.<div><br></div><div>Elie<br><br><div><div id="SkyDrivePlaceholder"></div>> Subject: Re: [Pw_forum] Irreps and vibrational modes<br>> From: giannozz@democritos.it<br>> To: elie.moujaes@hotmail.co.uk<br>> CC: pw_forum@pwscf.org<br>> Date: Mon, 14 May 2012 17:35:26 +0200<br>> <br>> On Mon, 2012-05-14 at 03:07 +0100, Elie M wrote:<br>> <br>> > (1) Are all the modes vibrational?<br>> <br>> there are always three translational modes<br>> <br>> > (2) Are any modes missing from the calculation<br>> <br>> there shouldn't be anything missing<br>> <br>> > (3) i did the calculation and got two of the modes negative<br>> <br>> if they go to zero when you apply the acoustic sum rule, with all<br>> other modes unchanged or litle affected, it is not a problem<br>> <br>> P.<br>> <br>> -- <br>> Paolo Giannozzi, IOM-Democritos and University of Udine, Italy<br>> <br>> <br></div></div> </div></body>
</html>