From owner-chemistry %-% at %-% ccl.net Tue Jun 22 18:33:00 2021 From: "Eduardo Lemos de Sa edulsa|-|ufpr.br" To: CCL Subject: CCL: Trying to get rotational radius (gaussian16) Message-Id: <-54414-210622183133-6376-CBtLwQUZYgDmNF2RU8WUrA.:.server.ccl.net> X-Original-From: "Eduardo Lemos de Sa" Date: Tue, 22 Jun 2021 18:31:32 -0400 Sent to CCL by: "Eduardo Lemos de Sa" [edulsa(~)ufpr.br] Dear I stall with a problem to calculate rotational radius in g16(c.01). At first, I found in output file: Molecular mass: 649.03443 amu. Principal axes and moments of inertia in atomic units: 1 2 3 Eigenvalues -- ****************************** X -0.18621 0.74195 0.64408 Y 0.95290 -0.02334 0.30238 Z -0.23939 -0.67005 0.70266 This molecule is an asymmetric top. Eigenvalues are written as ***** (I guess, it is a problem with number format), but I got principal axes. Is it possible to get eigenvalues from this? Other important point: "moments of inertia in atomic units". I guess mass are in a.m.u (or is in terms of mass of electron?) and distances are in Bohr radio (a_0). Please, am I correct? Further, there are lines bellow: ================================================== Analysis of the Rotor Symmetry ================================================== Framework Group : C1 Rotor Type : Asymmetric Top Asymm. param. : Kappa = -0.406425 Inertia moments : X= 7180.27334 , Y= 4731.16097 , Z= 6224.04915 Representation : IIr Representation, Iy < Iz < Ix Axes Definition for the Symmetric-Top Representation ---------------------------------------------------- Axis Z automatically chosen to be collinear with Y from Eckart orient. NOTE: In Vibro-rotational analysis, this will be referred to as the spectroscopic orientation. Please, is possible to get rotation radius from this inertia moments (there is no clue about units)? I tried: rotat_radius=sqrt(Inertia_X/mass/(a.m.u)) but, as I do not know which are the units for Inertia, I do not know if my results are in angstron or bohr_radio. Please, could you give some hints? Thank you in advance for your attention Yours Eduardo Universidade Federal do Parana/Curitiba/Brazil