Adam Wasserman

Density functional theory (DFT) is a quantum mechanical framework in which the ground state of interacting electronic systems is completely described in terms of the electron density. This leads to a practical approach for electronic structure calculations which is very widely used in (bio)chemistry, physics, and materials science due to its reasonable computational cost and useful accuracy. This textbook presents the basic concepts and features of DFT at an introductory level, suitable for undergraduate and beginning graduate students in science and engineering. Beginning with a brief review of elementary quantum mechanics, the book then introduces essential concepts such as many-body wave functions, orbitals, Slater determinants, functionals, and the variational principle. The fundamental theorems of DFT of Hohenberg and Kohn and Kohn and Sham are formulated and explained, followed by a case study of a one-dimensional model system to illustrate the self-consistent numerical solution of the Kohn-Sham equation. To use DFT in practice, the exchange-correlation energy functional must be approximated: the most important and widely used approximations are reviewed, including the local-density approximation, generalized gradient approximations, and hybrid functionals, explaining their origin and assessing their performance with many examples. Practical aspects of molecular and solid-state calculations, such as basis sets and pseudopotentials, are introduced, together with a brief review of chemical reactivity indices. The book ends with a chapter on time-dependent DFT, discussing real-time electron dynamics and excitation energies, and additional resources are provided in several appendices. Written in an accessible and student-friendly style, the book covers the essentials of DFT and electronic structure calculations in a fully self-contained manner and without overburdening readers with formal and technical details. The book also contains many end-of-chapter exercises, including hands-on computer simulations using Python, as well as many suggestions for further reading.

Density functional theory (DFT) is a quantum mechanical framework in which the ground state of interacting electronic systems is completely described in terms of the electron density. This leads to a practical approach for electronic structure calculations which is very widely used in (bio)chemistry, physics, and materials science due to its reasonable computational cost and useful accuracy. This textbook presents the basic concepts and features of DFT at an introductory level, suitable for undergraduate and beginning graduate students in science and engineering. Beginning with a brief review of elementary quantum mechanics, the book then introduces essential concepts such as many-body wave functions, orbitals, Slater determinants, functionals, and the variational principle. The fundamental theorems of DFT of Hohenberg and Kohn and Kohn and Sham are formulated and explained, followed by a case study of a one-dimensional model system to illustrate the self-consistent numerical solution of the Kohn-Sham equation. To use DFT in practice, the exchange-correlation energy functional must be approximated: the most important and widely used approximations are reviewed, including the local-density approximation, generalized gradient approximations, and hybrid functionals, explaining their origin and assessing their performance with many examples. Practical aspects of molecular and solid-state calculations, such as basis sets and pseudopotentials, are introduced, together with a brief review of chemical reactivity indices. The book ends with a chapter on time-dependent DFT, discussing real-time electron dynamics and excitation energies, and additional resources are provided in several appendices. Written in an accessible and student-friendly style, the book covers the essentials of DFT and electronic structure calculations in a fully self-contained manner and without overburdening readers with formal and technical details. The book also contains many end-of-chapter exercises, including hands-on computer simulations using Python, as well as many suggestions for further reading.

Angolina Reeves is a simple Ward of the State. In a yearstretch's time, she expects to graduate and become a full-fledged citizen. She will work hard, stay loyal, and if she's lucky one daystretch make it all the way to Alpha clearance. But in the Bunker - a utopian dreamland - disaster is never far away. And when it strikes, she finds herself trapped out in the dark. And so, together with an unhygienic smack addict by the name of Finian Flanagan and a mysterious stranger from the outside, she sets out to find her way back to civilization. Needled, cajoled, ramrodded, tormented, and bullied, Angolina is forced to contend with adults and in the process become one herself. But time is running out. For it isn't just cold and hunger that threaten her fragile innocence. Branded a traitor by Control, the Bunker's vast and all-knowing overseer, she must somehow redeem herself before it's too late.

Greetings, citizen. Your interest in Today's Edition has been noted by the authorities. By electing to access illegal, detrimental and highly subversive material, you have identified yourself as a traitor. Please turn yourself in to your Homeland Security neighborhood substation. Today's Edition does not exist. Rumors of a popular e-zine created by the Human Resources conglomerate and then spun off to the private sector are entirely false and should not be trusted. Likewise, no weekly publication in the Bunker was ever hijacked by traitors - repeatedly - as an instrument to achieve their own nefarious ends. How exactly you came to possess knowledge of Today's Edition and where it might once have allegedly been published is surely one of the topics your interrogator will be fond of discussing with you. Please be prepared to draw up a list of your fellow conspirators and which recent acts of sabotage, subterfuge, and calumny can be attributed to them. Thank you for your cooperation.

Welcome (back) to the Bunker, an orderly, underground utopia where everyone's needs have been satisfied. Barney Max is a trustworthy citizen with an impeccable record of achievement. But one daystretch on his way to Mars for an interplanetary conference, he finds himself added to the Thousand Most Wanted List. For no apparent reason at all. And he's allowed to walk free. Thus begins Barney Max's unexpected and entirely unwelcome journey. Deprived of his daily comforts, chased by a persistent headache (not to mention armed guardians from Defense, a secret society of vengeful cybots, and an angry mob of former employees), he is forced to confront a reality he has struggled his whole life to deny. The second in the Bunker series of sci-fi adventure novels, Your Call Is Important To Us can be read independently, although it is best enjoyed in the company of its predecessor, Thank You For Your Cooperation.

David Berkowitz attends the Johns Hopkins University in 1991 where he gets mixed up in drugs and insanity. Combined with a violent home life, David can't quite cope with his experiences. Later on, as the world crumbles around him, he remains curiously unaffected. For he is still held in thrall by the events that occurred in that short time - and the girl he loved and lost

Imagine a world where the outcome of political debate is arranged beforehand. Imagine a world where we are too busy working to care. Imagine a world where we get to feel good about ourselves. A farcical depiction of the struggles between the world's power brokers: the Holy Man and the Politician, and later on the Capitalist and Communist as well. They must eventually come to an end...