title: Effect of nuclear motion on the absorption spectrum of dipicolinic acid.
abstract: Using semiclassical electron-radiation-ion dynamics, the authors have examined the effect of nuclear motion, resulting from both finite temperature and the response to a radiation field, on the line broadening of the excitation profile of 2,6-pyridinedicarboxylic acid (dipicolinic acid). With nuclei fixed, there is a relatively small broadening associated with the finite time duration of an applied laser pulse. When the nuclei are allowed to move, the excitation spectrum exhibits a much larger broadening, and is also reduced in height and shifted toward lower frequencies. In both cases, the excitation is due to well-defined pi to pi* transitions. The further inclusion of thermal motion at room temperature broadens the linewidth considerably because of variations in the molecular geometry: Transitions that had zero or negligible transition probabilities in the ground state geometry are weakly excited at room temperature.
authors.affiliation: Department of Physics, Texas A&M University, College Station, Texas 77843, USA.
authors.forename: Petra
authors.initials: P
authors.lastname: Sauer
authors.forename: Yuri
authors.initials: Y
authors.lastname: Rostovtsev
authors.forename: Roland E
authors.initials: RE
authors.lastname: Allen
mesh_terms: D000465:Algorithms; D001408:Bacillus anthracis / Q000737:chemistry* / Q000302:isolation & purification*; D003198:Computer Simulation; D009682:Magnetic Resonance Spectroscopy / Q000379:methods*; D008956:Models, Chemical; D008958:Models, Molecular; D010848:Picolinic Acids / Q000032:analysis* / Q000737:chemistry*; D013171:Spores, Bacterial / Q000737:chemistry / Q000302:isolation & purification
chemical_list: D010848:Picolinic Acids; C004860:dipicolinic acid