Quantum chemistry and dynamics of excited states : methods and applications / Leticia González, Roland Lindh

**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. Cover -- Title Page -- Copyright -- Contents -- List of Contributors -- Preface -- Chapter 1 Motivation and Basic Concepts -- 1.1 Mission and Motivation -- 1.2 Atomic Units -- 1.3 The Molecular Hamiltonian -- 1.4 Dirac or Bra-Ket Notation -- 1.5 Index Definitions -- 1.6 Second Quantization Formalism -- 1.7 Born-Oppenheimer Approximation and Potential Energy Surfaces -- 1.8 Adiabatic Versus Diabatic Representations -- 1.9 Conical Intersections -- 1.10 Further Reading -- 1.11 Acknowledgments -- Part I Quantum Chemistry -- Chapter 2 Time-Dependent Density Functional Theory -- 2.1 Introduction -- 2.2 TDDFT Fundamentals -- 2.2.1 The Runge-Gross Theorems -- 2.2.2 The Time-Dependent Kohn-Sham Approach -- 2.2.3 Solutions of Time-Dependent Kohn-Sham Equations -- 2.2.3.1 Real-Time TDDFT -- 2.2.3.2 Linear-Response TDDFT -- 2.3 Linear-Response TDDFT in Action -- 2.3.1 Vertical Excitations and Energy Surfaces -- 2.3.1.1 Vertical Excitations: How Good are They? -- 2.3.1.2 Reconstructed Energy Surfaces: How Good are They? -- 2.3.2 Conical Intersections -- 2.3.3 Coupling Terms and Auxiliary Wave Functions -- 2.3.3.1 The Casida Ansatz -- 2.3.3.2 Time-Derivative Non-Adiabatic Couplings -- 2.3.4 Non-Adiabatic Dynamics -- 2.4 Excited States and Dynamics with TDDFT Variants and Beyond -- 2.5 Conclusions -- Acknowledgments -- References -- Chapter 3 Multi-Configurational Density Functional Theory: Progress and Challenges -- 3.1 Introduction -- 3.2 Wave Function Theory -- 3.3 Kohn-Sham Density Functional Theory -- 3.3.1 Density Functional Approximations -- 3.3.2 Density Functional Theory for Excited States -- 3.3.2.1 Issues Within the Time-Dependent Density Functional Theory Ansatz -- 3.3.2.2 Self-Interaction Error -- 3.3.2.3 Degeneracies, Near-Degeneracies and the Symmetry Dilemma -- 3.4 Multi-Configurational Density Functional Theory