Higher Excited States of Polyatomic Molecules, Volume II focuses on a higher level of activity in vacuum ultraviolet spectroscopy. This book explores the Rydberg states in atoms and molecules. Comprised of five chapters, this volume starts with an overview of the two-center unsaturated molecules that usually display sharp Rydberg transitions originating with the pi electrons. This book then discusses the unsaturated double bond that adds another dimension to the spectrum. Other chapters explore the optical spectrum of the amide group, which is the basic chromophoric unit in polypeptides. This text further discusses the all-electron calculations of the electronic structure of the amide group that is performed in Gaussian orbital basis sets. This book considers as well the prominent characteristic of Rydberg excitations in benzene. The final chapter deals with the biological molecules that are polyfunctional in general. Analytical chemists, photochemists, molecular spectroscopists, and researchers will find this book extremely useful.

Higher Excited States of Polyatomic Molecules, Volume III focuses on higher electronic excitations in polyatomic molecules, with emphasis on excitations beyond 50,000 cm-1. This book explores the various transitions on the basis of their orbital characteristics. Organized into 22 chapters, this volume begins with an overview of the relationships between spectra of different molecules and between the results of various types of spectroscopy. This book then discusses the higher excited states involving Rydberg excitation. Other chapters explore the higher excited states in all classes of biological, organic, and inorganic molecules. This text further discusses the progress in the area of higher excitations in polyatomic atoms and the technique of multiphoton ionization (MPI) spectroscopy that yields a remarkable amount of spectroscopic information applicable to the vacuum-ultraviolet region. The final chapter deals with the vacuum-ultraviolet spectroscopy of biological materials. Analytical chemists, photochemists, molecular spectroscopists, and researchers will find this book extremely useful.

Higher Excited States of Polyatomic Molecules, Volume II focuses on a higher level of activity in vacuum ultraviolet spectroscopy. This book explores the Rydberg states in atoms and molecules. Comprised of five chapters, this volume starts with an overview of the two-center unsaturated molecules that usually display sharp Rydberg transitions originating with the pi electrons. This book then discusses the unsaturated double bond that adds another dimension to the spectrum. Other chapters explore the optical spectrum of the amide group, which is the basic chromophoric unit in polypeptides. This text further discusses the all-electron calculations of the electronic structure of the amide group that is performed in Gaussian orbital basis sets. This book considers as well the prominent characteristic of Rydberg excitations in benzene. The final chapter deals with the biological molecules that are polyfunctional in general. Analytical chemists, photochemists, molecular spectroscopists, and researchers will find this book extremely useful.

Higher Excited States of Polyatomic Molecules, Volume I focuses on the spectra in the vacuum-ultraviolet region between 50,000 and 100,000 cm-1. This book explores the higher excitations in molecules beyond 50,000 cm-1. Organized into three chapters, this volume starts with an overview of the excited-state properties of a molecule and the excited-state ionization potential. This book then proceeds with a discussion of the original classification of the properties as well as the types of excitations observed in the vacuum-ultraviolet. Other chapters discuss photoelectron spectroscopy, which is an independent, self-sustaining branch of molecular spectroscopy. This text examines as well the distinction between valence shell and Rydberg excitations. The final chapter deals with several topics, including the saturated molecules that are classified as having all valence electrons, the alkene absorption spectra, and the spectroscopic data on boron compounds. Analytical chemists, photochemists, molecular spectroscopists, and researchers will find this book extremely useful.

Higher Excited States of Polyatomic Molecules, Volume I focuses on the spectra in the vacuum-ultraviolet region between 50,000 and 100,000 cm-1. This book explores the higher excitations in molecules beyond 50,000 cm-1. Organized into three chapters, this volume starts with an overview of the excited-state properties of a molecule and the excited-state ionization potential. This book then proceeds with a discussion of the original classification of the properties as well as the types of excitations observed in the vacuum-ultraviolet. Other chapters discuss photoelectron spectroscopy, which is an independent, self-sustaining branch of molecular spectroscopy. This text examines as well the distinction between valence shell and Rydberg excitations. The final chapter deals with several topics, including the saturated molecules that are classified as having all valence electrons, the alkene absorption spectra, and the spectroscopic data on boron compounds. Analytical chemists, photochemists, molecular spectroscopists, and researchers will find this book extremely useful.

Higher Excited States of Polyatomic Molecules, Volume III focuses on higher electronic excitations in polyatomic molecules, with emphasis on excitations beyond 50,000 cm-1. This book explores the various transitions on the basis of their orbital characteristics. Organized into 22 chapters, this volume begins with an overview of the relationships between spectra of different molecules and between the results of various types of spectroscopy. This book then discusses the higher excited states involving Rydberg excitation. Other chapters explore the higher excited states in all classes of biological, organic, and inorganic molecules. This text further discusses the progress in the area of higher excitations in polyatomic atoms and the technique of multiphoton ionization (MPI) spectroscopy that yields a remarkable amount of spectroscopic information applicable to the vacuum-ultraviolet region. The final chapter deals with the vacuum-ultraviolet spectroscopy of biological materials. Analytical chemists, photochemists, molecular spectroscopists, and researchers will find this book extremely useful.

From the beginnings of modern chemistry, molecular structure has been a lively area of research and speculation. For more than half a century spectroscopy and other methods have been available to characterize the structures and shapes of molecules, particularly those that are rigid. However, most molecules are at least to some degree non-rigid and this non-rigidity plays an important role in such diverse areas as biological activity, energy transfer, and chemical reactivity. In addition, the large-amplitude vibrations present in non-rigid molecules give rise to unusual low-energy vibrational level patterns which have a dramatic effect on the thermodynamic properties of these systems. Only in recent years has a coherent picture of the energetics and dynamics of the conformational changes inherent in non-rigid (and semi-rigid) molecules begun to emerge. Advances have been made in a number of different experimental areas: vibrational (infrared and Raman) spectroscopy, rotational (microwave) spectroscopy, electron diffraction, and, most recently, laser techniques probing both the ground and excited electronic states. Theoretically, the proliferation of powerful computers coupled with scientific insight has allowed both empirical and ab initio methods to increase our understanding of the forces responsible for the structures and energies of non-rigid systems. The development of theory (group theoretical methods and potential energy surfaces) to understand the unique characteristics of the spectra of these floppy molecules has also been necessary to reach our present level of understanding. The thirty chapters in this volume contributed by the key speakers at the Workshop are divided over the various areas. Both vibrational and rotational spectroscopy have been effective at determining the potential energy surfaces for non-rigid molecules, often in a complementary manner. Recent laser fluorescence work has extended these types of studies to electronic excited states. Electronic diffraction methods provide radial distribution functions from which both molecular structures and compositions of conformational mixtures can be found. Ab initio calculations have progressed substantially over the past few years, and, when carried out at a sufficiently high level, can accurately reproduce (or predict ahead of time) experimental findings. Much of the controversy of the ARW related to the question of when an ab initio is reliable. Since the computer programs are readily available, many poor calculations have been carried out. However, excellent results can be obtained from computations when properly done. A similar situation exists for experimental analyses. The complexities of non-rigid molecules are many, but major strides have been taken to understand their structures and conformational processes.

The aim of this volume is to offer a balanced overview of molecular Rydberg spectroscopy as it has developed over recent decades. Recent evolution has split Rydberg spectroscopy into two apparently distinct fields: the one concerns the low (n=3-5) Rydberg states, the other the very high (typically EMn/EM”150) Rydberg states. The former is aimed at spectral levels where Rydberg, valence-shell, and intermediate-type states interact, with a variety of photochemical consequences. The latter considers states extremely close to the ionization limit, from whereionization is possible with a very slight amount of additional energy. Recently developed techniques make it possible to produce ions in well-defined electronic, vibrational and rotational states, including states resulting from spin-orbit or Jahn-Teller splitting. It is then possible to study the structure and reactions of such state-selected ions as well as those of the corresponding neutral molecules. These techniques amount to badly needed high resolution photoelectron spectroscopy.

Frontiers and Advances in Molecular Spectroscopy once again brings together the most eminent scientists from around the world to describe their work at the cutting-edge of molecular spectroscopy. Much of what we know about atoms, molecules and the nature of matter has been obtained using spectroscopy over the last one hundred years or so. Going far beyond the topics discussed in Jaan Laane's earlier book on the subject, these chapters describe new methodologies and applications, instrumental developments and theory, which are taking spectroscopy into still new frontiers. The robust range of topics once again demonstrates the wide utility of spectroscopic techniques. New topics include ultrafast spectroscopy of the transition state, SERS/far-uv spectroscopy, femtosecond coherent anti-Stokes Raman spectroscopy, high-resolution laser induced fluorescence spectroscopy, Raman spectroscopy and biosensors, vibrational optical activity, ultrafast two-dimensional spectroscopy, biology with x-ray lasers, isomerization dynamics and hydrogen bonding, single molecule imaging, spectra of intermediates, matrix isolation spectroscopy and more. - Covers spectroscopic investigations on the cutting edge of science - Written and edited by leading experts in their respective fields - Allows researchers to access a broad range of essential modern spectroscopy content from a single source rather than wading through hundreds of scattered journal articles

This volume focuses on the use of quantum theory to understand and explain experiments in organic chemistry. High level ab initio calculations, when properly performed, are useful in making quantitative distinctions between various possible interpretations of structures, reactions and spectra. Chemical reasoning based on simpler quantum models is, however, essential to enumerating the likely possibilities. The simpler models also often suggest the type of wave function likely to be involved in ground and excited states at various points along reaction paths. This preliminary understanding is needed in order to select the appropriate higher level approach since most higher level models are designed to describe improvements to some reasonable zeroth order wave function. Consequently, most of the chapters in this volume begin with experimental facts and model functions and then progress to higher level theory only when quantitative results are required.In the first chapter, Zimmerman discusses a wide variety of thermal and photochemical reactions of organic molecules. Gronert discusses the use of ab initio calculations and experimental facts in deciphering the mechanism of ?-elimination reactions in the gas phase. Bettinger et al focus on carbene structures and reactions with comparison of the triplet and singlet states. Next, Hrovat and Borden discuss more general molecules with competitive triplet and singlet contenders for the ground state structure. Cave explains the difficulties and considerations involved with many of the methods and illustrates the difficulties by comparing with the UV spectra of short polyenes. Jordan et al discuss long-range electron transfer using model compounds and model Hamiltonians. Finally, Hiberty discusses the breathing orbital valence bond model as a different approach to introducing the crucial åã correlation that is known to be important in organic reactions.