Highly Accurate Spectroscopic Parameters from Ab Initio Calculations

Highly Accurate Spectroscopic Parameters from Ab Initio Calculations PDF Author: Christopher J. Stein
Publisher: Springer
ISBN: 3658148306
Category : Science
Languages : en
Pages : 63

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Book Description
In this thesis accurate predictions for the spectroscopic parameters of l-C3H+ and C4 are made from state-of-the-art electronic structure calculations. Both molecules are of interest to interstellar cloud chemistry and only scarce experimental information about their rovibrational properties is available. Christopher J. Stein recapitulates the basics of the computational methods applied and gives an in-depth description of the computer program developed for the rovibrational calculations.

Highly Accurate Spectroscopic Parameters from Ab Initio Calculations

Highly Accurate Spectroscopic Parameters from Ab Initio Calculations PDF Author: Christopher J. Stein
Publisher: Springer
ISBN: 3658148306
Category : Science
Languages : en
Pages : 63

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Book Description
In this thesis accurate predictions for the spectroscopic parameters of l-C3H+ and C4 are made from state-of-the-art electronic structure calculations. Both molecules are of interest to interstellar cloud chemistry and only scarce experimental information about their rovibrational properties is available. Christopher J. Stein recapitulates the basics of the computational methods applied and gives an in-depth description of the computer program developed for the rovibrational calculations.

Ab Initio Calculation of Spectroscopic Parameters

Ab Initio Calculation of Spectroscopic Parameters PDF Author: Shamshad Ahmad
Publisher:
ISBN:
Category : Atomic spectra
Languages : en
Pages :

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Book Description


Ab Initio Variational Calculations of Molecular Vibrational-Rotational Spectra

Ab Initio Variational Calculations of Molecular Vibrational-Rotational Spectra PDF Author: Debra J. Searles
Publisher: Springer Science & Business Media
ISBN: 3662055619
Category : Science
Languages : en
Pages : 245

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Book Description
This work had its beginnings in the early 1980s at the University ofWollongong, with significant contributions from Dr. Margret Hamilton, Professors Peter G. Burton and Greg Doherty. The emphasis was to develop computer code to solve the nuclear Schrodinger problem. For bent triatomic molecules the project was fmally realized at the University of Newcastle a decade or so later, with the contribution from Ms. Feng Wan g. Aspects of this work are now taught in the quantum mechanics and electron spectroscopy courses at The University of Newcastle. Even now "complete" ab initio solutions of the time-independent SchrOdinger equation is not commonplace for molecules containing four atoms or more. In fact, when using the Eckart-Watson nuclear Hamiltonian a further restriction needs to be imposed; that is, the molecule is restricted to undergoing small amplitudes of vibration. This Hamiltonian is useful for molecules containing massive nuclei and moreover, has been extremely useful in interpreting the rovibrational spectra of small molecules. Nevertheless, a number of nuclear Hamiltonians that do not embed an equilibrium geometry have become well established and are extremely successful in interpreting rovibrational spectra of floppy molecules. Furthermore, solution algorithms vary greatly from research group to research group and it is still unclear which aspects will survive the next decade. For example, even for a triatomic molecule a general form of a potential function has not yet been uncovered that will generally interpolate with accuracy and precision ab initio discrete surfaces.

Recent Experimental and Computational Advances in Molecular Spectroscopy

Recent Experimental and Computational Advances in Molecular Spectroscopy PDF Author: Rui Fausto
Publisher: Springer Science & Business Media
ISBN: 9401119740
Category : Science
Languages : en
Pages : 458

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Book Description
Both molecular spectroscopy and computational chemistry have witnessed rapid significant progresses in recent years. On the one hand, it is nowadays possible to compute, to quite a reasonable degree of accuracy, almost all fundamental spectroscopic properties for small molecular systems. The theoretical approach is now properly considered to be of fundamental importance in attaining a high degree of understanding of spectroscopic information. Moreover, it may be also a great help in designing and planning experiments. On the other hand, new and very powerful experimental techniques have been developed. This book combines an advanced teaching standpoint with an emphasis on the interplay between theoretical and experimental molecular spectroscopy. It covers a wide range of topics (such as molecular dynamics and reactivity, conformational analysis, hydrogen bonding and solvent effects, spectroscopy of excited states, complex spectra interpretation and simulation, software development and biochemical applications of molecular spectroscopy) and considers a large variety of molecular spectroscopic techniques, either from an experimental or from a theoretical perspective. (short text) This book combines an advanced teaching standpoint with an emphasis on the interplay between theoretical and experimental molecular spectroscopy. It covers a wide range of topics (such as molecular dynamics and reactivity, conformational analysis, hydrogen bonding and solvent effects, spectroscopy of excited states, complex spectra interpretation and simulation, software development and biochemical applications of molecular spectroscopy) and considers a large variety of molecular spectroscopic techniques either from an experimental or from a theoretical perspective.

The Application of Some Hartree-Fock Model Calculation to the Analysis of Atomic and Free-Ion Optical Spectra

The Application of Some Hartree-Fock Model Calculation to the Analysis of Atomic and Free-Ion Optical Spectra PDF Author:
Publisher:
ISBN:
Category :
Languages : en
Pages : 292

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Book Description
Techniques for applying ab-initio calculations to the is of atomic spectra are investigated, along with the relationship between the semi-empirical and ab-initio forms of Slater-Condon theory. Slater-Condon theory is reviewed with a focus on the essential features that lead to the effective Hamiltonians associated with the semi-empirical form of the theory. Ab-initio spectroscopic parameters are calculated from wavefunctions obtained via self-consistent field methods, while multi-configuration Hamiltonian matrices are constructed and diagonalized with computer codes written by Robert Cowan of Los Alamos Scientific Laboratory. Group theoretical analysis demonstrates that wavefunctions more general than Slater determinants (i.e. wavefunctions with radial correlations between electrons) lead to essentially the same parameterization of effective Hamiltonians. In the spirit of this analysis, a strategy is developed for adjusting ab-initio values of the spectroscopic parameters, reproducing parameters obtained by fitting the corresponding effective Hamiltonian. Secondary parameters are used to "screen" the calculated (primary) spectroscopic parameters, their values determined by least squares. Extrapolations of the secondary parameters determined from analyzed spectra are attempted to correct calculations of atoms and ions without experimental levels. The adjustment strategy and extrapolations are tested on the K I sequence from K{sup 0+} through Fe{sup 7+}, fitting to experimental levels for V{sup 4+}, and Cr{sup 5+}; unobserved levels and spectra are predicted for several members of the sequence. A related problem is also discussed: Energy levels of the Uranium hexahalide complexes, (UX6)2− for X= F, Cl, Br, and I, are fit to an effective Hamiltonian (the f2 configuration in O{sub h} symmetry) with corrections proposed by Brian Judd.

Handbook of High-resolution Spectroscopy

Handbook of High-resolution Spectroscopy PDF Author: Martin Quack
Publisher: John Wiley & Sons
ISBN: 0470066539
Category : Science
Languages : en
Pages : 2236

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Book Description
The field of High-Resolution Spectroscopy has been considerably extended and even redefined in some areas. Combining the knowledge of spectroscopy, laser technology, chemical computation, and experiments, Handbook of High-Resolution Spectroscopy provides a comprehensive survey of the whole field as it presents itself today, with emphasis on the recent developments. This essential handbook for advanced research students, graduate students, and researchers takes a systematic approach through the range of wavelengths and includes the latest advances in experiment and theory that will help and guide future applications. The first comprehensive survey in high-resolution molecular spectroscopy for over 15 years Brings together the knowledge of spectroscopy, laser technology, chemical computation and experiments Brings the reader up-to-date with the many advances that have been made in recent times Takes the reader through the range of wavelengths, covering all possible techniques such as Microwave Spectroscopy, Infrared Spectroscopy, Raman Spectroscopy, VIS, UV and VUV Combines theoretical, computational and experimental aspects Has numerous applications in a wide range of scientific domains Edited by two leaders in this field Provides an overview of rotational, vibration, electronic and photoelectron spectroscopy Volume 1 - Introduction: Fundamentals of Molecular Spectroscopy Volume 2 - High-Resolution Molecular Spectroscopy: Methods and Results Volume 3 - Special Methods & Applications

High Accuracy Resonator Spectroscopy of Atmospheric Gases at Millimetre and Submillimetre Waves

High Accuracy Resonator Spectroscopy of Atmospheric Gases at Millimetre and Submillimetre Waves PDF Author: M. Yu. Tretyakov
Publisher: Cambridge Scholars Publishing
ISBN: 1527577406
Category : Science
Languages : en
Pages : 425

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Book Description
This book is devoted to the most efficient method of obtaining spectroscopic parameters characterising the absorption of microwave radiation by the Earth’s atmosphere. It explores why this field of science is interesting and important for humanity, and details the basics of gas phase molecular spectroscopy. The book also shows the advantages of the resonator spectroscopy technique for quantitative molecular analysis, and reviews the best-known investigations of diagnostic atmospheric lines and the continuum in the millimetre and submillimetre-wave range. It will appeal to a wide range of specialists in the fields of spectroscopy, atmospheric physics, and millimetre and submillimetre-wave techniques, and will be helpful for lecturers and students concerned with these specialised courses.

Molecular Spectroscopy Volume 6

Molecular Spectroscopy Volume 6 PDF Author:
Publisher: Royal Society of Chemistry
ISBN: 0851865569
Category : Molecular spectra
Languages : en
Pages : 338

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Book Description
This product is not available separately, it is only sold as part of a set. There are 750 products in the set and these are all sold as one entity. Specialist Periodical Reports provide systematic and detailed review coverage of progress in the major areas of chemical research. Written by experts in their specialist fields the series creates a unique service for the active research chemist, supplying regular critical in-depth accounts of progress in particular areas of chemistry. For over 80 years the Royal Society of Chemistry and its predecessor, the Chemical Society, have been publishing reports charting developments in chemistry, which originally took the form of Annual Reports. However, by 1967 the whole spectrum of chemistry could no longer be contained within one volume and the series Specialist Periodical Reports was born. The Annual Reports themselves still existed but were divided into two, and subsequently three, volumes covering Inorganic, Organic and Physical Chemistry. For more general coverage of the highlights in chemistry they remain a 'must'. Since that time the SPR series has altered according to the fluctuating degree of activity in various fields of chemistry. Some titles have remained unchanged, while others have altered their emphasis along with their titles; some have been combined under a new name whereas others have had to be discontinued. The current list of Specialist Periodical Reports can be seen on the inside flap of this volume.

Accurate Structure Determination of Free Molecules

Accurate Structure Determination of Free Molecules PDF Author: Jean Demaison
Publisher: Springer Nature
ISBN: 3030604926
Category : Science
Languages : en
Pages : 291

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Book Description
This book presents a detailed look at experimental and computational techniques for accurate structure determination of free molecules. The most fundamental property of a molecule is its structure – it is a prerequisite for determining and understanding most other important properties of molecules. The determination of accurate structures is hampered by a myriad of factors, subjecting the collected data to non-negligible systematic errors. This book explains the origin of these errors and how to mitigate and even avoid them altogether. It features a detailed comparison of the different experimental and computation methods, explaining their interplay and the advantages of their combined use. Armed with this information, the reader will be able to choose the appropriate methods to determine – to a great degree of accuracy – the relevant molecular structure.

Comparison of Ab Initio Quantum Chemistry with Experiment for Small Molecules

Comparison of Ab Initio Quantum Chemistry with Experiment for Small Molecules PDF Author: R.J. Bartlett
Publisher: Springer Science & Business Media
ISBN: 9789027721297
Category : Gardening
Languages : en
Pages : 530

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Book Description
At the American Chemical Society meeting in Philadelphia, Pennsylvania, U.S.A., a symposium was organized entitled, "Comparison of Ab Initio Quantum Chemistry with Experiment: State-of-the-Art." The intent of the symposium was to bring together forefront experimen talists, who perform the types of clean, penetrating experiments that are amenable to thorough theoretical analysis, with inventive theore ticians who have developed high accuracy ab initio methods that are capable of competing favorably with experiment, to assess the current applicability of theoretical methods in chemistry. Contributions from many of those speakers (see Appendix A) plus others selected for their expertise in the subject are contained in this volume. Such a book is especially timely, since with the recent develop ment of new, more accurate and powerful ab initio methods coupled with the exceptional progress achieved in computational equipment, ab initio quantum chemistry is now often able to offer a third voice to resolve experimental discrepancies, assist essentially in the interpre tation of experiments, and frequently, provide quantitatively accurate results for molecular properties that are not available from experiment.