SEMINAR: Bayliss Seminar Series

Chemistry over the millennia has had many great successes, often despite fundamental knowledge of the actual processes involved. The advent of quantum mechanics a hundred years ago provides the modern basis for understanding these processes, but this theory depicts great complexity rather than the desired simplicity. As a result, modern chemical understanding has become partitioned into different theories for different applications, without any unifying overview. Many fundamental questions often result in an answer of “it does not matter”, but in modern contexts of nanotechnology and biotechnology involving interdisciplinary work, the nature of the bonding can become critical. For example, i) the nature of Au-S bonding is critical to the understanding of nanoparticle synthesis and spectroscopy,1-3 ii) understanding the difference in shapes and reactivity between second-row molecules and later analogues requires focusing on Rydberg orbital properties,12 iii) aromaticity and isomerization reactions have the one common origin,5 iv) van der Waals forces control many aspects of device assembly and materials properties,9 v) breakdown of the Born- Oppenheimer approximation controls many critical properties such as the nature of light absorption by chlorophyll4 and primary charge separation in bacterial photosynthesis,11 and vi) chemical entanglement can be described for all processes,13 including neural ones.7 This lecture, dedicated to David Craig, proposes a simple and unified way to treat all processes from the bond in hydrogen to aromaticity to metallic bonding using the same chemical language and notation, allowing these diverse processes to be quantitatively compared one to another.5 It provides answers to fundamental chemical problems unsolved for the last 20,13 30,1-3 50,4 80,5,6 or 10012 years, showing how to make better molecules and devices in the future.