Share

Recent Advances in Multireference Methods

1999 Science
Download Recent Advances in Multireference Methods PDF Online Free

Author :
Release : 1999
Genre : Science
Kind : eBook
Book Rating : 776/5 ( reviews)

GET EBOOK


Book Synopsis Recent Advances in Multireference Methods by : Kimihiko Hirao

Download or read book Recent Advances in Multireference Methods written by Kimihiko Hirao. This book was released on 1999. Available in PDF, EPUB and Kindle. Book excerpt: Recently, accurate ab initio quantum computational chemistry has evolved dramatically. In particular, the development of multireference-based approaches has opened up a whole new area and has also had a profound impact on the potential of theoretical chemistry. The multiconfigurational SCF (MCSCF)/CASSCF method is an attempt to generalize the Hartree-Fock (HF) model and to treat real chemical processes, where nondynamic correlation is important, while keeping the conceptual simplicity of the HF model as much as possible. Although MCSCF/CASSCF itself does not include dynamic correlations, it provides a good starting point for such studies. There are three approaches to handling dynamic correlations. Beginning with the MSSCF/CASSCF wave function, they are the variational (MRCI), perturbational (MRPT) and cluster expansion (MRCC) approaches. This important book presents the most recent and important developments in multireference-based approaches and their applications. Its main purpose is to highlight essential aspects of the frontiers of multireference theory and provide readers with the fundamental knowledge necessary for further development.

Recent Advances in Coupled-cluster Methods

1997 Science
Download Recent Advances in Coupled-cluster Methods PDF Online Free

Author :
Release : 1997
Genre : Science
Kind : eBook
Book Rating : 125/5 ( reviews)

GET EBOOK


Book Synopsis Recent Advances in Coupled-cluster Methods by : Rodney J. Bartlett

Download or read book Recent Advances in Coupled-cluster Methods written by Rodney J. Bartlett. This book was released on 1997. Available in PDF, EPUB and Kindle. Book excerpt: Today, coupled-cluster (CC) theory has emerged as the most accurate, widely applicable approach for the correlation problem in molecules. Furthermore, the correct scaling of the energy and wavefunction with size (i.e. extensivity) recommends it for studies of polymers and crystals as well as molecules. CC methods have also paid dividends for nuclei, and for certain strongly correlated systems of interest in field theory.In order for CC methods to have achieved this distinction, it has been necessary to formulate new, theoretical approaches for the treatment of a variety of essential quantities. These include properties and, particularly, analytical first derivatives (gradients) that readily provide the forces on the atoms in a molecule to facilitate searching potential energy surfaces for structures and transition states; second derivatives (Hessians) which indicate the type of extremum point and provide vibrational frequencies and intensities; excited, ionized, and electron attached states including their properties; multi-configurational reference functions to add important non-dynamic correlation; and relativistic effects.This book addresses very recent work in each of the above topics in ten chapters written by leading experts in molecular CC theory. This is NOT a collection of reviews, but is, instead, forefront research explained in an unusually clear exposition. Each chapter presents new results and formulations that offer another step toward providing the next generation of powerful CC solutions.The gap that often exists between text books and research can be more of a chasm in highly technical fields like CC theory, but this volume helps to fill the void, as it provides a sequel to a graduate level course in CC theory and many-electron methods. Essentially all current directions for new research are well represented in the authoritative articles.

Recent Advances in Relativistic Molecular Theory

2004 Science
Download Recent Advances in Relativistic Molecular Theory PDF Online Free

Author :
Release : 2004
Genre : Science
Kind : eBook
Book Rating : 905/5 ( reviews)

GET EBOOK


Book Synopsis Recent Advances in Relativistic Molecular Theory by : Kimihiko Hirao

Download or read book Recent Advances in Relativistic Molecular Theory written by Kimihiko Hirao. This book was released on 2004. Available in PDF, EPUB and Kindle. Book excerpt: Relativistic effects, though minor in light atoms, increase rapidly in magnitude as the atomic number increases. For heavy atom species, it becomes necessary to discard the SchrAdinger equation in favor of the Dirac equation. Construction of an effective many-body Hamiltonian that accurately accounts for both relativistic and electron correlation effects in many-electron systems is a challenge. It is only in the past 20OCo25 years that relativistic quantum chemistry has emerged as a field of research in its own right, and it seems certain that relativistic many-electron calculations of molecular properties will assume increasing importance in the years ahead as relativistic quantum chemistry finds a wider range of applications.With the increasing use of relativistic quantum chemical techniques in chemistry, there is an obvious need to provide experts' reviews of the methods and algorithms. This volume aims to disseminate aspects of relativistic many-electron theories and their exciting developments by practitioners. Together, the nine chapters provide an in-depth account of the most important topics of contemporary research in relativistic quantum chemistry, ranging from quasirelativistic effective core potential methods to relativistic coupled cluster theory."

Quantum Chemistry and Dynamics of Excited States

2021-02-01 Science
Download Quantum Chemistry and Dynamics of Excited States PDF Online Free

Author :
Release : 2021-02-01
Genre : Science
Kind : eBook
Book Rating : 759/5 ( reviews)

GET EBOOK


Book Synopsis Quantum Chemistry and Dynamics of Excited States by : Leticia González

Download or read book Quantum Chemistry and Dynamics of Excited States written by Leticia González. This book was released on 2021-02-01. Available in PDF, EPUB and Kindle. Book excerpt: An introduction to the rapidly evolving methodology of electronic excited states For academic researchers, postdocs, graduate and undergraduate students, Quantum Chemistry and Dynamics of Excited States: Methods and Applications reports the most updated and accurate theoretical techniques to treat electronic excited states. From methods to deal with stationary calculations through time-dependent simulations of molecular systems, this book serves as a guide for beginners in the field and knowledge seekers alike. Taking into account the most recent theory developments and representative applications, it also covers the often-overlooked gap between theoretical and computational chemistry. An excellent reference for both researchers and students, Excited States provides essential knowledge on quantum chemistry, an in-depth overview of the latest developments, and theoretical techniques around the properties and nonadiabatic dynamics of chemical systems. Readers will learn: ● Essential theoretical techniques to describe the properties and dynamics of chemical systems ● Electronic Structure methods for stationary calculations ● Methods for electronic excited states from both a quantum chemical and time-dependent point of view ● A breakdown of the most recent developments in the past 30 years For those searching for a better understanding of excited states as they relate to chemistry, biochemistry, industrial chemistry, and beyond, Quantum Chemistry and Dynamics of Excited States provides a solid education in the necessary foundations and important theories of excited states in photochemistry and ultrafast phenomena.

Recent Progress In Orbital-free Density Functional Theory

2013-03-08 Science
Download Recent Progress In Orbital-free Density Functional Theory PDF Online Free

Author :
Release : 2013-03-08
Genre : Science
Kind : eBook
Book Rating : 747/5 ( reviews)

GET EBOOK


Book Synopsis Recent Progress In Orbital-free Density Functional Theory by : Yan Alexander Wang

Download or read book Recent Progress In Orbital-free Density Functional Theory written by Yan Alexander Wang. This book was released on 2013-03-08. Available in PDF, EPUB and Kindle. Book excerpt: This is a comprehensive overview of state-of-the-art computational methods based on orbital-free formulation of density functional theory completed by the most recent developments concerning the exact properties, approximations, and interpretations of the relevant quantities in density functional theory.The book is a compilation of contributions stemming from a series of workshops which had been taking place since 2002. It not only chronicles many of the latest developments but also summarises some of the more significant ones. The chapters are mainly reviews of sub-domains but also include original research.

You may also like...