Spectroscopy, molecular

The identification of excited states in strong field interactions with molecules has lead to some novel forms of molecular spectroscopy, allowing previously inaccessible states to be studied. For the most part, this comes from the ability to do transient spectroscopy in the time domain with ultrashort pulses. But, the strong field interaction also allows for new population mechanisms. 

The energy states associated with molecules, like those of atoms, are also quantized. There are very powerful spectroscopic methods for studying transitions between permitted states in molecules using radiation from the radiowave region to the UV region. These methods provide qualitative and quantitative information about molecules, including detailed information about molecular structure. 

This section extends the basic spectroscopic concepts we developed in Section 8.1 from hydrogen atoms to molecules. As we noted in Chapter 6, we cannot completely solve Schrodinger s equations for anything more complicated than a hydrogen atom, except by computer. However, many properties of the spectra of the simplest molecules (diatomic molecules) are quite simple and very useful. 

The classical description in Chapter 2 separated molecular motions into translations, rotations, and vibrations. Each of these motions is treated differently in a quantum mechanical picture. In addition, electrons in molecules can be moved to higher energy levels, just as electrons in a hydrogen atom had multiple energy levels. We will treat each of these cases in turn. 

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Burdett, R.A., L.W. Taylor and L.C. Jones Jr (1955), Determination of aromatic hydrocarbons in lubricating oil fractions by far UV absorption spectroscopy , p. 30. In Molecular Spectroscopy Report Conf. Institute of Petroleum, London. 

The importance of the particle levitation methods is that they allow the study of how a single particle responds to changes in environment. The infrared molecular spectroscopy of single particles is possible [253], as are photophysical studies using adsorbed or dissolved dyes. 

The analogous coupling between the antisyimnetric stretch and bend is forbidden in the H2O Hamiltonian because of syimnetry.) The 2 1 resonance is known as a Femii resonance after its introduction [ ] in molecular spectroscopy. The 2 1 resonance is often very prominent in spectra, especially between stretch and bend modes, which often have approximate 2 1 frequency ratios. The 2 1 couplmg leaves unchanged as a poly ad number the sum ... 

Scherer N F, Carlson R J, Matro A, Du M, Ruggiero A J, Romero-Rochin V, Cina J A, Fleming G R and Rice S A 1991 Fluorescence-detected wave packet interferometry time resolved molecular spectroscopy with sequences of femtosecond phase-locked pulses J. Chem. Rhys. 95 1487... 

Quack M and Kutzelnigg W 1995 Molecular spectroscopy and molecular dynamics theory and experiment Ber. Bunsenges. Rhys. Chem. 99 231-45... 

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

Heller E J 1981 The semiclassical way to molecular spectroscopy Accounts Chem. Res. 14 368-75... 

This book, originally published in 1950, is the first of a classic tliree-volume set on molecular spectroscopy. A rather complete discussion of diatomic electronic spectroscopy is presented. Volumes 11 (1945) and 111 (1967) discuss infrared and Raman spectroscopy and polyatomic electronic spectroscopy, respectively. 

Molecular spectroscopy offers a fiindamental approach to intramolecular processes [18, 94]. The spectral analysis in temis of detailed quantum mechanical models in principle provides the complete infomiation about the wave-packet dynamics on a level of detail not easily accessible by time-resolved teclmiques. 

Smith MAH, Rinsland C P and Fridovich B 1985 Intensities and collision broadening parameters from infrared spectra Molecular Spectroscopy Modem Research Volume Hied K N Rao (New York Academic) pp 118-19... 

B. A. Hess and C. M. Marian, Relativistic Effects in the Calculation of the Electronic Energy, in Computational Molecular Spectroscopy, P. Jensen and P. Bunker, eds., John Wiley Sc Sons, Inc., Chichester, UK, 2000, pp. 169-220. 

We find it convenient to reverse the historical ordering and to stait with (neatly) exact nonrelativistic vibration-rotation Hamiltonians for triatomic molecules. From the point of view of molecular spectroscopy, the optimal Hamiltonian is that which maximally decouples from each other vibrational and rotational motions (as well different vibrational modes from one another). It is obtained by employing a molecule-bound frame that takes over the rotations of the complete molecule as much as possible. Ideally, the only remaining motion observable in this system would be displacements of the nuclei with respect to one another, that is, molecular vibrations. It is well known, however, that such a program can be realized only approximately by introducing the Eckart conditions [38]. 

P. Jensen and P. R. Buenker, eds., Computational Molecular Spectroscopy, John Wiley and Sons, Inc., 2000. 

G. Duxbury, Molecular Spectroscopy, Vol. 3, Billing Sons, Guilford and London, 1975,p. 497. 

T. N. Levine, Molecular Spectroscopy, John Wiley Sons, Tnc., New York, 1975. 

Brown, J. B., 1998. Molecular Spectroscopy. Oxford Univ. Press, Oxford. 

The treatment of electronic motion is treated in detail in Sections 2, 3, and 6 where molecular orbitals and configurations and their computer evaluation is covered. The vibration/rotation motion of molecules on BO surfaces is introduced above, but should be treated in more detail in a subsequent course in molecular spectroscopy. 

This completes our introduction to the subject of molecular spectroscopy. More advanced treatments of many of the subjects treated here as well as many aspects of modern experimental spectroscopy can be found in the text by Zare on angular momentum as well as in Steinfeld s text Molecules and Radiation, 2 Edition, by J. I. Steinfeld, MIT Press (1985). 

C. E. Dykstra, Quantum Chemistry Molecular Spectroscopy Prentice Haii, Engiewood Ciiffs (1992). 

Principles of Molecular Spectroscopy Quantized Energy States... 

PRINCIPLES OF MOLECULAR SPECTROSCOPY QUANTIZED ENERGY STATES... 

W. S. Stmve, Fundamentals of Molecular Spectroscopy,Wiley Sons, Inc., New York, 1989. 

C. R. Brundle. In Molecular Spectroscopy. K. R. West, Ed.) Heyden, London, 1976. This review discusses both the use of XPS and UPS in studying adsorption and reactions at surfaces. 

J. B. Birks, in, (Wiley and Sons, London, 1970). A general review of the molecular spectroscopy of aromatic molecules. 

Organic Magnetic Resonance (now Magn Reson Chem ) Progress in Nuclear Magnetic Resonance Spectroscopy Spectrochimica Acta Part A Molecular Spectroscopy Spectroscopy Letters Spectroscopy An International Journal... 

J. B. Foresman and H. B. Schlegel, Application of the Cl-Singles Method in Predicting the Energy, Properties and Reactivity of Molecules in Their Excited Slates in Molecular Spectroscopy Recent Experimental and Computational Advances, ed. R. Fausto, NATO-ASI Series C, Kluwer Academic, The Netherlands, 1993. 

C N Banwell, Fundamentals of Molecular Spectroscopy, 3rd edn, McGraw-Hill, London, 1983... 

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