Molecular Spectroscopy An Introduction

A schematic representation of two electronic energy levels in a molecule, with the vibrational (in red) and rotational (in blue) energy levels shown for each electronic state. 

A schematic representation of two molecular electronic states with the accompanying vibrational and rotational energy levels is given in Fig. 14.52. Note that each electronic energy level has a set of quantized vibrational states and that each vibrational state has a set of rotational states. 

Depending on the energy of the photons interacting with it, a molecule can undergo a pure rotational transition (change rotational levels but remain in the same vibrational and electronic states), a vibrational transition that may also involve a simultaneous rotational transition (see Fig. 14.53), or an electronic 

The various types of transitions are shown by vertical arrows. Note that rotational changes are lowest in energy, followed by vibrational changes and then electronic changes, which require the highest-energy photons. 

Marrin, Localized and Spectroscopic Orbitals Squirrel Ears on Warer, /. Chem. Ed-65 (1988) 688. 

Scerri, Have Orbirals Really Been Observed , j. Chem. Ed. 77 (2000) 1492. 

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D. C. Harris andM. D. Bertolucci, Symmetry and Spectroscopy An Introduction to Vibrational and Electronic Spectroscopy , Oxford University Press, New York, 1979. Easy-to-follow, instructive textbook on vibrational and electronic spectroscopy with numerous helpful figures, line drawings, and exercises illustrating important concepts. Excellent choice for anyone teaching or studying molecular spectroscopy at jimior to beginning graduate level. Also available in paperback from Dover, New York. 

B. Lambert and E. P. Mazzola, Nuclear Magnetic Resonarwe Spectroscopy, An Introduction to Principles, Applications, and Experimental Methods, Pearson Education, Upper Saddle River, NJ, 2004. (d) J. M. Blaney and J. S. Dixon, Distance Geometry in Molecular Modeling, Reviews in Computational Chemistry, Vol. 5, K. B. Lipkowitz and D. B. Boyd, Eds., Wiley, New York, 1994, p. 299. 

Herzberg G 1971 The Spectra and Structures of Simple Free Radicals An Introduction to Molecular Spectroscopy (Ithaca, NY Cornell University Press)... 

This is an introduction to the techniques used for the calculation of electronic excited states of molecules (sometimes called eximers). Specifically, these are methods for obtaining wave functions for the excited states of a molecule from which energies and other molecular properties can be calculated. These calculations are an important tool for the analysis of spectroscopy, reaction mechanisms, and other excited-state phenomena. 

The spin-Hamiltonian concept, as proposed by Van Vleck [79], was introduced to EPR spectroscopy by Pryce [50, 74] and others [75, 80, 81]. H. H. Wickmann was the first to simulate paramagnetic Mossbauer spectra [82, 83], and E. Miinck and P. Debmnner published the first computer routine for magnetically split Mossbauer spectra [84] which then became the basis of other simulation packages [85]. Concise introductions to the related modem EPR techniques can be found in the book by Schweiger and Jeschke [86]. Magnetic susceptibility is covered in textbooks on molecular magnetism [87-89]. An introduction to MCD spectroscopy is provided by [90-92]. Various aspects of the analysis of applied-field Mossbauer spectra of paramagnetic systems have been covered by a number of articles and reviews in the past [93-100]. 

Throughout the book I have tried to constrain the wonders of imagination inspired by the subject by using simple calculations. Can all of the water on the Earth have been delivered by comets if so, how many comets How do I use molecular spectroscopy to work out what is happening in a giant molecular cloud Calculations form part of the big hard-sell for astrochemistry and they provide a powerful control against myth. I have aimed the book at second-year undergraduates who have had some exposure to quantum mechanics, kinetics, thermodynamics and mathematics but the book could easily be adapted as an introduction to all of these areas for a minor course in chemistry to stand alone. 

The book is separated into five major sections One short section on general aspects of spectroscopy, molecular biology and data evaluation is followed by an introduction into the NMR of commonly encountered classes of biomolecules. Thereafter, recent developments in spectroscopic techniques are highlighted. The next section describes experiments and practical aspects useful for the characterization of protein-ligand interactions. The final section presents an account on strategies for drug development using NMR written by experts from pharmaceutical industry. 

J.I. Steinfeld. Molecules and Radiation An Introduction to Modern Molecular Spectroscopy. Harper and Row, New York, 1974. 

Barrow, G., Introduction to Molecular Spectroscopy, McGraw-Hill, New York, 1962. An introductory text for undergraduates. 

Since the photochemical reaction is initiated by absorption of light in the visible, ultraviolet, and vacuum ultraviolet regions, an understanding of atomic and molecular spectroscopy is required. Chapter I gives a brief introduction to the electronic stales and transitions in atoms and simple molecules. 

A basic understanding of the quantum theory is essential in many areas of chemistry, especially in connection with spectroscopy and with theories of atomic and molecular structure. The present book gives an introduction to the theory, and its application to elementary atomic structure, but chemical bonding is not discussed. I have tried to put the essential ideas in their historical context, but without retaining the historical introduction which has been traditional with this topic. With the crucial and difficult concepts of wave-particle duality, it seemed to me more important to give modem illustrations to show that they have current applications in chemistry. 

A number of reviews can be consulted for an introduction to the fundamentals both theoretical and practical covering XPS. These include Riggs and Parker (2) and the book by Carlson (3). Electron spectroscopy is reviewed in alternate years in the Fundamental Reviews issue of Analytical Chemistry. The last literature review was published in 1980 (4) and this and previous reviews can be consulted for a coverage of all aspects of the literature of XPS. A number of recent symposia have been held on applications of surface analytical methods in various aspects of materials science such as the symposium on characterization of molecular structures of polymers by photon, electron, and ion probes at the March 1980 American Chemical Society meetings in Houston ( 5) and the International Symposium on Physiochemical Aspects of Polymer Surfaces at this meeting as well as the symposium on industrial applications of surface analysis of which this article is a part. Review articles on various applications of XPS in materials science are listed in Table I. 

In the weakly anharmonic molecular crystal the natural modes of vibration are collective, with each internal vibrational state of the molecules forming a band of elementary excitations called vibrons, in order to distinguish them from low-frequency lattice vibrations known as phonons. Unlike isolated impurities in matrices, vibrons may be studied by Raman spectroscopy, which has lead to the establishment of a large body of data. We will briefly attempt to summarize some of the salient experimental and theoretical results as an introduction to some new developments in this field, which have mainly been incited by picosecond coherent techniques. 

Empirical energy functions were originally developed for energy minimization and molecular dynamics studies of macromolecular structure and function (see [31], for an introduction). The parameters of the empirical potential energy Echem are inferred from experimental as well as theoretical investigations, in particular, vibrational spectroscopy and small-molecule crystallography [25-30],... 

An Introduction to Molecular Spectroscopy. The George Fisher Baker Non-Resident Lectureship in Chemistry at Cornell University. Ithaca, N.Y. Cornell University Press, 1971. 

R. L. Carter (1998) Molecular Symmetry and Group Theory, Wiley, New York - An introduction to molecular S5mmetry and group theory as applied to chemical problems including vibrational spectroscopy. 

Raman spectroscopy now has become a powerful technique of considerable sensitivity for probing the identities, structures, bonding, and reaction dynamics of molecular species at electrode surfaces. Although the literature on this topic already is extensive, it is the aim of this review to provide an introduction to this still novel spectroscopic technique, to give a glimpse of some of its achievements to date, and to indicate the directions in which further progress is likely to be made in the near future. 

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