Computational Advances In Organic Chemistry

Download Computational Advances In Organic Chemistry full books in PDF, epub, and Kindle. Read online Computational Advances In Organic Chemistry ebook anywhere anytime directly on your device. Fast Download speed and no annoying ads. We cannot guarantee that every ebooks is available!

Computational Advances in Organic Chemistry: Molecular Structure and Reactivity

Author : Cemil Ögretir
Publisher : Springer Science & Business Media
ISBN 13 : 9401132623
Total Pages : 424 pages
Book Rating : 4.4/5 (11 download)

DOWNLOAD NOW!

Book Synopsis Computational Advances in Organic Chemistry: Molecular Structure and Reactivity by : Cemil Ögretir

Download or read book Computational Advances in Organic Chemistry: Molecular Structure and Reactivity written by Cemil Ögretir and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 424 pages. Available in PDF, EPUB and Kindle. Book excerpt: The lecturers as well as the participants came from varied scientific backgrOlUldsfor the NATO -Advanced Study Institute (ASDheld atAltinoluk, Edremit. Turkey during the period of July 31 -August 12 1989. The lecturers were University Professors from the USA, Canada, England, C'-.ermany, France and Spain and they covered a broad spectrwn of specialities from methodology t.o appications. On the other hand students coming from the various NATO countries arrived with an inhomogeneous background to absorb the broad spectnUIl of material covered by the lecturers. However, by the end of the two week period of the ASI, that initial difference in scientific background had been reduced substantially . The lecturers had covered subject matters from the most fundamental to the most applied aspects of theoretical and computational organic chemistry. The lectures were argnmented with tutorial sessions and computational laboratory led by a small group of carefnlly selected tutors. Overall, this NATO -ASI was a ~at success and the Editors are hopeful that the present volume will communicate the scientific success and will radiate the intellectual spirit of the meeting.

Computational Advances in Organic Chemistry

Author : Cemil Ogretir
Publisher :
ISBN 13 : 9789401132633
Total Pages : 434 pages
Book Rating : 4.1/5 (326 download)

DOWNLOAD NOW!

Book Synopsis Computational Advances in Organic Chemistry by : Cemil Ogretir

Download or read book Computational Advances in Organic Chemistry written by Cemil Ogretir and published by . This book was released on 1990-12-31 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Computational Organic Chemistry

Author : Steven M. Bachrach
Publisher : John Wiley & Sons
ISBN 13 : 1118291921
Total Pages : 653 pages
Book Rating : 4.1/5 (182 download)

DOWNLOAD NOW!

Book Synopsis Computational Organic Chemistry by : Steven M. Bachrach

Download or read book Computational Organic Chemistry written by Steven M. Bachrach and published by John Wiley & Sons. This book was released on 2014-04-07 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Second Edition demonstrates how computational chemistry continues to shed new light on organic chemistry The Second Edition of author Steven Bachrach’s highly acclaimed Computational Organic Chemistry reflects the tremendous advances in computational methods since the publication of the First Edition, explaining how these advances have shaped our current understanding of organic chemistry. Readers familiar with the First Edition will discover new and revised material in all chapters, including new case studies and examples. There’s also a new chapter dedicated to computational enzymology that demonstrates how principles of quantum mechanics applied to organic reactions can be extended to biological systems. Computational Organic Chemistry covers a broad range of problems and challenges in organic chemistry where computational chemistry has played a significant role in developing new theories or where it has provided additional evidence to support experimentally derived insights. Readers do not have to be experts in quantum mechanics. The first chapter of the book introduces all of the major theoretical concepts and definitions of quantum mechanics followed by a chapter dedicated to computed spectral properties and structure identification. Next, the book covers: Fundamentals of organic chemistry Pericyclic reactions Diradicals and carbenes Organic reactions of anions Solution-phase organic chemistry Organic reaction dynamics The final chapter offers new computational approaches to understand enzymes. The book features interviews with preeminent computational chemists, underscoring the role of collaboration in developing new science. Three of these interviews are new to this edition. Readers interested in exploring individual topics in greater depth should turn to the book’s ancillary website www.comporgchem.com, which offers updates and supporting information. Plus, every cited article that is available in electronic form is listed with a link to the article.

A Laboratory Book of Computational Organic Chemistry

Author : Warren J. Hehre
Publisher :
ISBN 13 : 9780964349551
Total Pages : 291 pages
Book Rating : 4.3/5 (495 download)

DOWNLOAD NOW!

Book Synopsis A Laboratory Book of Computational Organic Chemistry by : Warren J. Hehre

Download or read book A Laboratory Book of Computational Organic Chemistry written by Warren J. Hehre and published by . This book was released on 1998 with total page 291 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Computational Organic Chemistry

Author : Steven M. Bachrach
Publisher : John Wiley & Sons
ISBN 13 : 1118671228
Total Pages : 653 pages
Book Rating : 4.1/5 (186 download)

DOWNLOAD NOW!

Book Synopsis Computational Organic Chemistry by : Steven M. Bachrach

Download or read book Computational Organic Chemistry written by Steven M. Bachrach and published by John Wiley & Sons. This book was released on 2014-03-03 with total page 653 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Second Edition demonstrates how computational chemistry continues to shed new light on organic chemistry The Second Edition of author Steven Bachrach’s highly acclaimed Computational Organic Chemistry reflects the tremendous advances in computational methods since the publication of the First Edition, explaining how these advances have shaped our current understanding of organic chemistry. Readers familiar with the First Edition will discover new and revised material in all chapters, including new case studies and examples. There’s also a new chapter dedicated to computational enzymology that demonstrates how principles of quantum mechanics applied to organic reactions can be extended to biological systems. Computational Organic Chemistry covers a broad range of problems and challenges in organic chemistry where computational chemistry has played a significant role in developing new theories or where it has provided additional evidence to support experimentally derived insights. Readers do not have to be experts in quantum mechanics. The first chapter of the book introduces all of the major theoretical concepts and definitions of quantum mechanics followed by a chapter dedicated to computed spectral properties and structure identification. Next, the book covers: Fundamentals of organic chemistry Pericyclic reactions Diradicals and carbenes Organic reactions of anions Solution-phase organic chemistry Organic reaction dynamics The final chapter offers new computational approaches to understand enzymes. The book features interviews with preeminent computational chemists, underscoring the role of collaboration in developing new science. Three of these interviews are new to this edition. Readers interested in exploring individual topics in greater depth should turn to the book’s ancillary website www.comporgchem.com, which offers updates and supporting information. Plus, every cited article that is available in electronic form is listed with a link to the article.

Applied Theoretical Organic Chemistry

Author : Tantillo Dean J
Publisher : World Scientific
ISBN 13 : 1786344106
Total Pages : 624 pages
Book Rating : 4.7/5 (863 download)

DOWNLOAD NOW!

Book Synopsis Applied Theoretical Organic Chemistry by : Tantillo Dean J

Download or read book Applied Theoretical Organic Chemistry written by Tantillo Dean J and published by World Scientific. This book was released on 2018-03-07 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides state-of-the-art information on how studies in applied theoretical organic chemistry are conducted. It highlights the many approaches and tools available to those interested in using computational chemistry to predict and rationalize structures and reactivity of organic molecules. Chapters not only describe theoretical techniques in detail, but also describe recent applications and offer practical advice. Authored by many of the world leaders in the field of applied theoretical chemistry, this book is perfect for both practitioners of computational chemistry and synthetic and mechanistic organic chemists curious about applying computational techniques to their research. Contents: Modeling Organic Reactions — General Approaches, Caveats, and Concerns (Stephanie R Hare, Brandi M Hudson and Dean J Tantillo)Overview of Computational Methods for Organic Chemists (Edyta M Greer and Kitae Kwon)Brief History of Applied Theoretical Organic Chemistry (Steven M Bachrach)Solvation (Carlos Silva Lopez and Olalla Nieto Faza)Conformational Searching for Complex, Flexible Molecules (Alexander C Brueckner, O Maduka Ogba, Kevin M Snyder, H Camille Richardson and Paul Ha-Yeon Cheong)NMR Prediction (Kelvin E Jackson and Robert S Paton)Energy Decomposition Analysis and Related Methods (Israel Fernández)Systems with Extensive Delocalization (L Zoppi and K K Baldridge)Modern Treatments of Aromaticity (Judy I-Chia Wu)Weak Intermolecular Interactions (Rajat Maji and Steven E Wheeler)Predicting Reaction Pathways from Reactants (Romain Ramozzi, W M C Sameera and Keiji Morokuma)Unusual Potential Energy Surfaces and Nonstatistical Dynamic Effects (Charles Doubleday)The Distortion/Interaction Model for Analysis of Activation Energies of Organic Reactions (K N Houk, Fang Liu, Yun-Fang Yang and Xin Hong)Spreadsheet-Based Computational Predictions of Isotope Effects (O Maduka Ogba, John D Thoburn and Daniel J O'Leary)Stereoelectronic Effects: Analysis by Computational and Theoretical Methods (Gabriel dos Passos Gomes and Igor Alabugin)pKa Prediction (Yijie Niu and Jeehiun K Lee)Issues Particular to Organometallic Reactions (Gang Lu, Huiling Shao, Humair Omer and Peng Liu)Computationally Modeling Nonadiabatic Dynamics and Surface Crossings in Organic Photoreactions (Arthur Winter)Challenges in Predicting Stereoselectivity (Elizabeth H Krenske) Readership: Practitioners of computational chemistry and synthetic and mechanistic organic chemists curious about applying computational techniques to their research. Keywords: Organic Chemistry;Theoretical Chemistry;Stereoselectivity;NMR Prediction;pKa Prediction;Organic PhotoreactionsReview: Key Features: A particular strength is the mix of theoretical background, informative examples and practical advice providedChapters are authored by many of world leaders in the field of applied theoretical chemistry

Computational Theoretical Organic Chemistry

Author : Imre G. Csizmadia
Publisher : Springer Science & Business Media
ISBN 13 : 9400984723
Total Pages : 428 pages
Book Rating : 4.4/5 (9 download)

DOWNLOAD NOW!

Book Synopsis Computational Theoretical Organic Chemistry by : Imre G. Csizmadia

Download or read book Computational Theoretical Organic Chemistry written by Imre G. Csizmadia and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 428 pages. Available in PDF, EPUB and Kindle. Book excerpt: As a general rule any interdisciplinary subject and that includes Computational Theoretical Organic Chemistry (CTOC) incorporates people from the two overlaping areas. In this case the overlaping areas are Computational Theoretical Chemistry and Organic Chemistry. Since CTOC is a relatively young science, people continue to shift from their major discipline to this area. At this particular time in history we have to accept in CTOC people who were trained in Computational Theoretical Chemistry and do not know very much about Organic Chemistry, but more often the opposite case is operative Experimental Organic Chemistry who have not been exposed to Computational Theoretical Chemistry. This situation made NATO Advanced Study Institute in the field of CTOC necessary. The inhomogenity outlined above was present in the NATO Advanced Study Institute, held at Menton in July 1980, and to some degree it is noticable from the content of this volume. This book contains 20 contributions. The first contribution is an Introduc tion chapter in which the initiated experimental chemists are briefed about the subject matter. The last chapter describes very briefly the "Computational Laboratory" that was designed to help people with an experimental back ground in order to obtain some first hand experience. Between the first and the last chapters there are 18 contributions. These contributions were arranged in a spectrum from the exclusively method oriented papers to the applications of existing computational methods to problems of interest in Organic Chemistry.

Advanced Organic Chemistry

Author : Francis A. Carey
Publisher : Springer Science & Business Media
ISBN 13 : 0387448993
Total Pages : 1216 pages
Book Rating : 4.3/5 (874 download)

DOWNLOAD NOW!

Book Synopsis Advanced Organic Chemistry by : Francis A. Carey

Download or read book Advanced Organic Chemistry written by Francis A. Carey and published by Springer Science & Business Media. This book was released on 2007-06-27 with total page 1216 pages. Available in PDF, EPUB and Kindle. Book excerpt: The two-part, fifth edition of Advanced Organic Chemistry has been substantially revised and reorganized for greater clarity. The material has been updated to reflect advances in the field since the previous edition, especially in computational chemistry. Part A covers fundamental structural topics and basic mechanistic types. It can stand-alone; together, with Part B: Reaction and Synthesis, the two volumes provide a comprehensive foundation for the study in organic chemistry. Companion websites provide digital models for study of structure, reaction and selectivity for students and exercise solutions for instructors.

Advances in Physical Organic Chemistry

Author :
Publisher : Academic Press
ISBN 13 : 0128050810
Total Pages : 292 pages
Book Rating : 4.1/5 (28 download)

DOWNLOAD NOW!

Book Synopsis Advances in Physical Organic Chemistry by :

Download or read book Advances in Physical Organic Chemistry written by and published by Academic Press. This book was released on 2016-10-25 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advances in Physical Organic Chemistry series is the definitive resource for authoritative reviews of work in physical organic chemistry. It aims to provide a valuable source of information not only for physical organic chemists applying their expertise to both novel and traditional problems, but also for non-specialists across diverse areas who identify a physical organic component in their approach to research. Its hallmark is a quantitative, molecular level understanding of phenomena across a diverse range of disciplines. Reviews the application of quantitative and mathematical methods to help readers understand chemical problems Provides the chemical community with authoritative and critical assessments of the many aspects of physical organic chemistry Covers organic, organometallic, bioorganic, enzymes, and materials topics Presents the only regularly published resource for reviews in physical organic chemistry Written by authoritative experts who cover a wide range of topics that require a quantitative, molecular-level understanding of phenomena across a diverse range of disciplines

Essentials of Computational Chemistry

Author : Christopher J. Cramer
Publisher : John Wiley & Sons
ISBN 13 : 1118712277
Total Pages : 624 pages
Book Rating : 4.1/5 (187 download)

DOWNLOAD NOW!

Book Synopsis Essentials of Computational Chemistry by : Christopher J. Cramer

Download or read book Essentials of Computational Chemistry written by Christopher J. Cramer and published by John Wiley & Sons. This book was released on 2013-04-29 with total page 624 pages. Available in PDF, EPUB and Kindle. Book excerpt: Essentials of Computational Chemistry provides a balanced introduction to this dynamic subject. Suitable for both experimentalists and theorists, a wide range of samples and applications are included drawn from all key areas. The book carefully leads the reader thorough the necessary equations providing information explanations and reasoning where necessary and firmly placing each equation in context.

Organic Stereochemistry

Author : Hua-Jie Zhu
Publisher : John Wiley & Sons
ISBN 13 : 3527338225
Total Pages : 336 pages
Book Rating : 4.5/5 (273 download)

DOWNLOAD NOW!

Book Synopsis Organic Stereochemistry by : Hua-Jie Zhu

Download or read book Organic Stereochemistry written by Hua-Jie Zhu and published by John Wiley & Sons. This book was released on 2015-08-10 with total page 336 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adopting a novel approach to the topic by combining theoretical knowledge and practical results, this book presents the most popular and useful computational and experimental methods applied for studying the stereochemistry of chemical reactions and compounds. The text is clearly divided into three sections on fundamentals, spectroscopic and computational techniques, and applications in organic synthesis. The first part provides a brief introduction to the field of chirality and stereochemistry, while the second part covers the different methodologies, such as optical rotation, electronic circular dichroism, vibrational circular dicroism, and Raman spectroscopy. The third section then goes on to describe selective examples in organic synthesis, classified by reaction type, i.e. enantioselective, chemoselective and stereoselective reactions. A final chapter on total synthesis of natural products rounds off the book. A valuable reference for researchers in academia and industry working in the field of organic synthesis, computational chemistry, spectroscopy or medicinal chemistry.

Advanced Organic Chemistry

Author : Francis A. Carey
Publisher : Springer Science & Business Media
ISBN 13 : 038768350X
Total Pages : 1344 pages
Book Rating : 4.3/5 (876 download)

DOWNLOAD NOW!

Book Synopsis Advanced Organic Chemistry by : Francis A. Carey

Download or read book Advanced Organic Chemistry written by Francis A. Carey and published by Springer Science & Business Media. This book was released on 2007-09-06 with total page 1344 pages. Available in PDF, EPUB and Kindle. Book excerpt: The two-part, fifth edition of Advanced Organic Chemistry has been substantially revised and reorganized for greater clarity. The material has been updated to reflect advances in the field since the previous edition, especially in computational chemistry. Part B describes the most general and useful synthetic reactions, organized on the basis of reaction type. It can stand-alone; together, with Part A: Structure and Mechanisms, the two volumes provide a comprehensive foundation for the study in organic chemistry. Companion websites provide digital models for students and exercise solutions for instructors.

Practical Aspects of Computational Chemistry V

Author : Jerzy Leszczynski
Publisher : Springer Nature
ISBN 13 : 3030832449
Total Pages : 292 pages
Book Rating : 4.0/5 (38 download)

DOWNLOAD NOW!

Book Synopsis Practical Aspects of Computational Chemistry V by : Jerzy Leszczynski

Download or read book Practical Aspects of Computational Chemistry V written by Jerzy Leszczynski and published by Springer Nature. This book was released on 2021-10-21 with total page 292 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents contributions on a wide range of computational research applied to fields ranging from molecular systems to bulk structures. This volume highlights current trends in modern computational chemistry and discusses the development of theoretical methodologies, state-of-the-art computational algorithms and their practical applications. This volume is part of a continuous effort by the editors to document recent advances by prominent researchers in the area of computational chemistry. Most of the chapters are contributed by invited speakers and participants to International annual conference “Current Trends in Computational Chemistry”, organized by Jerzy Leszczynski, one of the editors of the current volume. This conference series has become an exciting platform for eminent theoretical and computational chemists to discuss their recent findings and is regularly honored by the presence of Nobel laureates. Topics covered in the book include reactive force-field methodologies, coarse-grained modeling, DNA damage radiosensitizers, modeling and simulation of surfaces and interfaces, non-covalent interactions, and many others. The book is intended for theoretical and computational chemists, physical chemists, material scientists and those who are eager to apply computational chemistry methods to problems of chemical and physical importance. It is a valuable resource for undergraduate, graduate and PhD students as well as for established researchers.

Computational Advances of Rh-Catalyzed C–H Functionalization

Author : Yu Lan
Publisher : Springer Nature
ISBN 13 : 9811604320
Total Pages : 132 pages
Book Rating : 4.8/5 (116 download)

DOWNLOAD NOW!

Book Synopsis Computational Advances of Rh-Catalyzed C–H Functionalization by : Yu Lan

Download or read book Computational Advances of Rh-Catalyzed C–H Functionalization written by Yu Lan and published by Springer Nature. This book was released on 2021-02-26 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book offers a comprehensive overview of recent theoretical studies on rhodium-catalyzed C-H functionalization, a topic that has attracted considerable attention over the years. It includes a brief experimental history, elementary reactions, and theoretical perspectives and describes in detail recent advanced computational studies on different types of Rh-catalyzed C-H functionalization, the underlying mechanisms, and the origin of regioselectivity in a series of such reactions. Providing examples shows readers how to use theoretical tools to solve problems related to mechanisms of organometallic reactions. As such, the book is an interesting and useful resource for a wide readership in various fields involving synthetic organic, organometallic, and catalysis reactions.

Theoretical and Computational Models for Organic Chemistry

Author : S.J. Formosinho
Publisher : Springer Science & Business Media
ISBN 13 : 9401135843
Total Pages : 445 pages
Book Rating : 4.4/5 (11 download)

DOWNLOAD NOW!

Book Synopsis Theoretical and Computational Models for Organic Chemistry by : S.J. Formosinho

Download or read book Theoretical and Computational Models for Organic Chemistry written by S.J. Formosinho and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 445 pages. Available in PDF, EPUB and Kindle. Book excerpt: The papers in this volume were presented at the NATO Advanced Study Institute held in Porto Novo, Portugal, August 26 - September 8, 1990. The Institute has been able to cover a wide spectrum of the Theoretical and Computational Models for organic molecules and organic reactions, ranging from the ab initio to the more empirical approaches, in the tradition established in the previous Institutes at S. Feliu de Guixols (Spain) and Altinoluk (Turkey). The continuity with this work was achieved by inviting half of the lecturers present in those meetings. But other important subjects were also covered at Porto Novo by new lecturers, both from universities and the industry. Molecular Mechanics, Protein Structure and Unidimensional Models were introduced by the first time. The concept of building on the expertise already acquired and available, both in terms of methods and contents, to develop in new directions, was appreciated by participants and lecturers. The Institute first considered the fundamentals of molecular orbital computations and ab initio methods and the construction of Potential Energy Surfaces. These subjects were further explored in several applications related with optimization of equilibrium geometries and transition structures. Practical examples were studied in Tutorial sessions and solved in the computational projects making use of the Gaussian 88 and Gaussian 90 programs. Empirical models can be complementary to the quantum-mechanical ones in equilibrium geometry optimizations.

Enabling Tools and Techniques for Organic Synthesis

Author : Stephen G. Newman
Publisher : John Wiley & Sons
ISBN 13 : 1119855632
Total Pages : 500 pages
Book Rating : 4.1/5 (198 download)

DOWNLOAD NOW!

Book Synopsis Enabling Tools and Techniques for Organic Synthesis by : Stephen G. Newman

Download or read book Enabling Tools and Techniques for Organic Synthesis written by Stephen G. Newman and published by John Wiley & Sons. This book was released on 2023-09-26 with total page 500 pages. Available in PDF, EPUB and Kindle. Book excerpt: Provides the practical knowledge of how new technologies impact organic synthesis, enabling the reader to understand literature, evaluate different techniques, and solve synthetic challenges In recent years, new technologies have impacted organic chemistry to the point that they are no longer the sole domain of dedicated specialists. Computational chemistry, for example, can now be used by organic chemists to help predict outcomes, understand selectivity, and decipher mechanisms. To be prepared to solve various synthetic problems, it is increasingly important for chemists to familiarize themselves with a range of current and emerging tools and techniques. Enabling Tools and Techniques for Organic Synthesis A Practical Guide to Experimentation, Automation, and Computation provides a broad overview of contemporary research and new technologies applied to organic synthesis. Detailed chapters, written by a team of experts from academia and industry, describe different state-of-the-art techniques such as computer-assisted retrosynthesis, spectroscopy prediction with computational chemistry, high throughput experimentation for reaction screening, and robotic and automated data collection methods. Emphasizing real-world practicality, the book includes chapters on programming for synthetic chemists, Machine Learning (ML) in chemical synthesis, concepts and applications of computational chemistry, and more. Highlights the most recent methods in organic synthesis and describes how to employ these techniques in a reader’s own research Familiarize readers with the application of computational chemistry and automation technology in organic synthesis Introduces synthetic chemists to electrochemistry, photochemistry, and flow chemistry Helps readers comprehend the literature, assess the strengths and limitations of each technique, and apply those tools to solve synthetic challenges Provides case studies and guided examples with graphical illustrations in each chapter Enabling Tools and Techniques for Organic Synthesis: A Practical Guide to Experimentation, Automation, and Computation is an invaluable reference for scientists needing an up-to-date introduction to new tools, graduate students wanting to expand their organic chemistry skills, and instructors teaching courses in advanced techniques for organic synthesis.

Advanced Organic Chemistry

Author : Francis A. Carey
Publisher : Springer
ISBN 13 : 9780387683461
Total Pages : 1203 pages
Book Rating : 4.6/5 (834 download)

DOWNLOAD NOW!

Book Synopsis Advanced Organic Chemistry by : Francis A. Carey

Download or read book Advanced Organic Chemistry written by Francis A. Carey and published by Springer. This book was released on 2008-05-27 with total page 1203 pages. Available in PDF, EPUB and Kindle. Book excerpt: The two-part, fifth edition of Advanced Organic Chemistry has been substantially revised and reorganized for greater clarity. The material has been updated to reflect advances in the field since the previous edition, especially in computational chemistry. Part A covers fundamental structural topics and basic mechanistic types. It can stand-alone; together, with Part B: Reaction and Synthesis, the two volumes provide a comprehensive foundation for the study in organic chemistry. Companion websites provide digital models for study of structure, reaction and selectivity for students and exercise solutions for instructors.