<span dir="ltr" aria-label="Translated text: Dear Jürg and Frederick, Thank you very much for your reply. Yes, I perform a geometry optimization calculation before starting the frequency calculation, optimizing all the parameters. In response to Jürg Hutter: I perform an optimization calculation on an isolated organic molecule, setting PERIODIC NONE and using POISSON_SOLVER ANALYTIC, followed by a frequency calculation." style="line-height: 36px; background-color: rgb(248, 249, 250); border: none; padding: 2px 0.14em 2px 0px; position: relative; margin: -2px 0px; resize: none; font-family: inherit; overflow: hidden; width: 270px; white-space-collapse: preserve; overflow-wrap: break-word; color: rgb(31, 31, 31);">Dear Jürg and Frederick, Thank you very much for your reply. Yes, I perform a geometry optimization calculation before starting the frequency calculation, optimizing all the parameters. In response to Jürg : I perform an optimization calculation on an isolated organic molecule, setting PERIODIC NONE and using POISSON_SOLVER ANALYTIC, followed by a frequency calculation.<div><span dir="ltr" aria-label="Translated text: Dear Jürg and Frederick, Thank you very much for your reply. Yes, I perform a geometry optimization calculation before starting the frequency calculation, optimizing all the parameters. In response to Jürg Hutter: I perform an optimization calculation on an isolated organic molecule, where I set PERIODIC NONE and use POISSON_SOLVER ANALYTIC, followed by a frequency calculation. For now, I'm only studying the isolated molecule; the periodic system will follow as soon as I understand how it works." style="line-height: 36px; background-color: rgb(248, 249, 250); border: none; padding: 2px 0.14em 2px 0px; position: relative; margin: -2px 0px; resize: none; font-family: inherit; overflow: hidden; width: 270px; white-space-collapse: preserve; overflow-wrap: break-word; color: rgb(31, 31, 31);">For now, I'm only studying the isolated molecule; the periodic system will follow as soon as I understand how it works. <span dir="ltr" aria-label="Translated text: The coordinates in the input file are obtained from a geometry optimization calculation performed with Gaussian. I took the coordinates as-is from the Gaussian output file." style="line-height: 36px; background-color: rgb(248, 249, 250); border: none; padding: 2px 0.14em 2px 0px; position: relative; margin: -2px 0px; resize: none; font-family: inherit; overflow: hidden; width: 270px; white-space-collapse: preserve; overflow-wrap: break-word; color: rgb(31, 31, 31);">The coordinates in the input file are obtained from a geometry optimization calculation performed with Gaussian. I took the coordinates as-is from the Gaussian output file.</div><div><span dir="ltr" aria-label="Translated text: The coordinates in the input file are obtained from a geometry optimization calculation performed with Gaussian. I took the coordinates as-is from the Gaussian output file." style="line-height: 36px; background-color: rgb(248, 249, 250); border: none; padding: 2px 0.14em 2px 0px; position: relative; margin: -2px 0px; resize: none; font-family: inherit; overflow: hidden; width: 270px; white-space-collapse: preserve; overflow-wrap: break-word; color: rgb(31, 31, 31);"><span dir="ltr" aria-label="Translated text: I have attached all the files." style="line-height: 36px; border: none; padding: 2px 0.14em 2px 0px; position: relative; margin: -2px 0px; resize: none; font-family: inherit; overflow: hidden; width: 270px; overflow-wrap: break-word;">I have attached all the files. <span dir="ltr" aria-label="Translated text: Thanks again for your help" style="line-height: 36px; border: none; padding: 2px 0.14em 2px 0px; position: relative; margin: -2px 0px; resize: none; font-family: inherit; overflow: hidden; width: 270px; overflow-wrap: break-word;">Thanks again for your help.</div><div><span dir="ltr" aria-label="Translated text: The coordinates in the input file are obtained from a geometry optimization calculation performed with Gaussian. I took the coordinates as-is from the Gaussian output file." style="line-height: 36px; background-color: rgb(248, 249, 250); border: none; padding: 2px 0.14em 2px 0px; position: relative; margin: -2px 0px; resize: none; font-family: inherit; overflow: hidden; width: 270px; white-space-collapse: preserve; overflow-wrap: break-word; color: rgb(31, 31, 31);">Sihem </div><div class="gmail_quote"><div dir="auto" class="gmail_attr">On Friday, March 14, 2025 at 10:49:02 AM UTC+1 Jürg Hutter wrote: </div><blockquote class="gmail_quote" style="margin: 0 0 0 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">Hi are you running using a supercell (periodic) or have you set PERIODIC NONE for CELL and POISSON Solver ? Default is to only remove 3 translations in periodic calculations, no rotations will be removed (3 further frequencies). regards JH ________________________________________ From: <a href data-email-masked rel="nofollow">cp...@googlegroups.com</a> <<a href data-email-masked rel="nofollow">cp...@googlegroups.com</a>> on behalf of Sihem AZIZI <<a href data-email-masked rel="nofollow">sihema...@gmail.com</a>> Sent: Thursday, March 13, 2025 10:26 PM To: cp2k Subject: [CP2K:21281] frequencies Dear all, I'm trying to calculate the frequencies of an organic molecule, and each time I get two or three negative values. I don't understand why. When I do the same thing with Gaussian, all the values are positive. Can you help me? Thank you. -- You received this message because you are subscribed to the Google Groups "cp2k" group. 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