Dear Netters, Since DMol(DFT software form Biosym, version 2.36) calculates 3N-6 frequencies, it dos not match for linear molecules (there are 3N-5 frequencies). Is there a possibility to evaluate the last frequency? Is it a degenerated frequency which is lacking? In this case, which one? Thank you in advance for your comments. Frederic Bouyer Lab. Electrochimie, ENSCP, Paris-France bouyer %-% at %-% ext.jussieu.fr http://alcyone.enscp.jussieu.fr/