Ti_2:Accurate Determination of the Dissociation Energy from Matrix Resonance Raman Spectra and Chemical Interaction With Noble Gases

摘要

UV-visible and resonance Raman spectra of Ti_2 isolated in Ar,Kr,and Xe matrices at temperatures of 10 K were measured by using the 514 nm line of an Ar ion laser.The data show that the Ti_2 molecule interacts strongly with Xe,leading to a significant weakening of the Ti-Ti bond strength.The/(Ti-Ti)force constant decreases in the series Ar>Kr>Xe,from 232.8 Nm~(-1)in Ar and 225.5 Nm~(-1)in Kr to 199.7 Nm~(-1)in Xe.Additional experiments in an Ar matrix containing 2% of Xe indicate the formation of a molecule of the formula Ti_2Xe.Our spectra for Ti_2 in an Ar matrix give evidence for several previously not ob-served members of the Stokes progression.The sum of experimental data allows for an improved estimation of the dissociation energy on the basis of a LeRoy-Bernstein-Lam analysis.A dissociation energy of 1.18eV was derived from this analysis.The UV-visible data give evidence of the vibrational levels of an excited state of Ti_2.