Unimolecular Reactions

Author(s):  
Niels Engholm Henriksen ◽  
Flemming Yssing Hansen

This chapter considers unimolecular reactions; photo-induced reactions, that is, true unimolecular reactions; and reactions initiated by collisional activation, that is, apparent unimolecular reactions where it is assumed that the time scales for activation and subsequent reaction are well separated. Elements of classical and quantum dynamical descriptions are discussed, including Slater theory and the quantum mechanical description of photo-induced reactions. Statistical theories aiming at the calculation of micro-canonical as well as canonical rate constants are discussed, including a detailed discussion of RRKM theory. It concludes with a discussion of femtochemistry, that is, the observation and control of chemical dynamics using femtosecond pulses of electromagnetic radiation, focusing on the control of unimolecular reactions via the interaction with coherent light; that is, laser control.

2016 ◽  
pp. 4039-4042
Author(s):  
Viliam Malcher

The interpretation problems of quantum theory are considered. In the formalism of quantum theory the possible states of a system are described by a state vector. The state vector, which will be represented as |ψ> in Dirac notation, is the most general form of the quantum mechanical description. The central problem of the interpretation of quantum theory is to explain the physical significance of the |ψ>. In this paper we have shown that one of the best way to make of interpretation of wave function is to take the wave function as an operator.


2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Zbigniew Dutkiewicz

AbstractDrug design is an expensive and time-consuming process. Any method that allows reducing the time the costs of the drug development project can have great practical value for the pharmaceutical industry. In structure-based drug design, affinity prediction methods are of great importance. The majority of methods used to predict binding free energy in protein-ligand complexes use molecular mechanics methods. However, many limitations of these methods in describing interactions exist. An attempt to go beyond these limits is the application of quantum-mechanical description for all or only part of the analyzed system. However, the extensive use of quantum mechanical (QM) approaches in drug discovery is still a demanding challenge. This chapter briefly reviews selected methods used to calculate protein-ligand binding affinity applied in virtual screening (VS), rescoring of docked poses, and lead optimization stage, including QM methods based on molecular simulations.


2006 ◽  
Vol 106 (9) ◽  
pp. 2129-2144 ◽  
Author(s):  
Luiz Antônio S. Costa ◽  
Trevor W. Hambley ◽  
Willian R. Rocha ◽  
Wagner B. De Almeida ◽  
Hélio F. Dos Santos

2015 ◽  
Vol 6 ◽  
pp. 1946-1956 ◽  
Author(s):  
Nikolay V Klenov ◽  
Alexey V Kuznetsov ◽  
Igor I Soloviev ◽  
Sergey V Bakurskiy ◽  
Olga V Tikhonova

We present our approach for a consistent, fully quantum mechanical description of the magnetization reversal process in natural and artificial atomic systems by means of short magnetic pulses. In terms of the simplest model of a two-level system with a magnetic moment, we analyze the possibility of a fast magnetization reversal on the picosecond timescale induced by oscillating or short unipolar magnetic pulses. We demonstrate the possibility of selective magnetization reversal of a superconducting flux qubit using a single flux quantum-based pulse and suggest a promising, rapid Λ-scheme for resonant implementation of this process. In addition, the magnetization reversal treatment is fulfilled within the framework of the macroscopic theory of the magnetic moment, which allows for the comparison and explanation of the quantum and classical behavior.


2007 ◽  
Vol 51 (2) ◽  
pp. 367-375 ◽  
Author(s):  
A. Westphal ◽  
H. Abele ◽  
S. Baeßler ◽  
V.V. Nesvizhevsky ◽  
K.V. Protasov ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document