Knowledge-based spectroscopic assignment Jin Wang a , Bradford G. Nickerson b, * , Ronald M. Lees c , Li-Hong Xu d a Nokia Mobile Phones, Inc., 12278 Scripss Summit Drive, San Diego, CA 92131, USA b Faculty of Computer Science, Information Technology Centre, University of New Brunswick, P.O. Box 4400, 550 Windsor Street, Room ITC 304, Fredericton, N.B. Canada, E3B 5A3 c Physics Department, University of New Brunswick, Fredericton, N.B. Canada d Department of Physical Sciences, University of New Brunswick, Saint John, N.B. Canada Received 18 May 1999; received in revised form 3 December 1999; accepted 17 November 2000 Abstract Studying the energy level structure of dierent molecules by means of spectroscopy is one of the ®elds in physics and chemistry. In this paper, we describe a knowledge-based system, molecular spectroscopic assignment assistant MOSAA), which can assist researchers in the assignment of the far-infrared and infrared absorption peaks of the molecules in question by using the spectral information provided, along with a knowledge base containing known ground-state energy levels of the given molecules and spectroscopic assignment rules provided by researchers. A total of 313 rules together with their associated components i.e., parameters, functions and properties) compose the knowledge base for MOSAA. A speci®c inference engine was designed to handle the ``trial and error'' process requiredforspectroscopicassignment.AnoverviewofMOSAAaswellasthetestingresultsarediscussedinthispaper. Testing of the CH 18 3 OH and CD 16 3 OH spectra showed that MOSAA successfully assigned 11 testing series for each spectrum in 1/8 of the time on average required to do a manual assignment. Two series of the CD 16 3 OH spectrum assignedbyMOSAAweremissedintheoriginalmanualassignment. Ó 2001ElsevierScienceB.V.Allrightsreserved. Keywords: Spectroscopy;Molecularspectroscopicassignment;Methanol;Knowledge-basedsystem;Physicsknowledgebase;Inference engine 1. Introduction Studyingtheenergylevelstructureofdierentmoleculesbymeansofspectroscopyisoneofthe ®eldsinPhysicsandChemistry.Methanol,oneofthesimplestandmostimportantmoleculeswith hinderedinternalrotation,hasreceivedattentioninPhysicsandChemistrysinceearly1940[12]. Recently, several researchers have studied rotational and vibrational energy levels of methanol and its isotopic species [13,17,22±24]. In the last decade, the technique of high-resolution Fourier transform spectroscopy has had tremendous quantitative impact on the study of methanol [22]. The method involves ®rst Data & Knowledge Engineering 37 2001) 217±242 www.elsevier.com/locate/datak * Corresponding author. Tel.: +1-506-458-7278; fax: +1-506-451-6976. E-mail address: bgn@unb.ca B.G. Nickerson). 0169-023X/01/$ - see front matter Ó 2001 Elsevier Science B.V. All rights reserved. PII: S0169-023X00)00056-2