Dynamics of the reaction CH2OH+ .fwdarw. CHO+ + H2. Translational energy release from ab initio trajectory calculations

1992 ◽  
Vol 114 (11) ◽  
pp. 4265-4268 ◽  
Author(s):  
Einar Uggerud ◽  
Trygve Helgaker
Keyword(s):  
Ab Initio ◽  
Energy Release ◽  
Translational Energy ◽  
Trajectory Calculations

scholarly journals Toward fully quantum modelling of ultrafast photodissociation imaging experiments. Treating tunnelling in the ab initio multiple cloning approach

2016 ◽  
Vol 194 ◽  
pp. 81-94 ◽  
Author(s):  
Dmitry V. Makhov ◽  
Todd J. Martinez ◽  
Dmitrii V. Shalashilin
Keyword(s):  
Kinetic Energy ◽  
Ab Initio ◽  
Energy Release ◽  
Kinetic Energy Release ◽  
Total Kinetic Energy ◽  
Recent Effort ◽  
Experimental Measurements ◽  
Quantum Level ◽  
Hydrogen Atoms ◽  
Quantum Simulations

We present an account of our recent effort to improve simulation of the photodissociation of small heteroaromatic molecules using the Ab Initio Multiple Cloning (AIMC) algorithm. The ultimate goal is to create a quantitative and converged technique for fully quantum simulations which treats both electrons and nuclei on a fully quantum level. We calculate and analyse the total kinetic energy release (TKER) spectra and Velocity Map Images (VMI), and compare the results directly with experimental measurements. In this work, we perform new extensive calculations using an improved AIMC algorithm that now takes into account the tunnelling of hydrogen atoms. This can play an extremely important role in photodissociation dynamics.

Multiscale Analysis of Silicon LPCVD Reactor

2005 ◽  
Author(s):  
Yukinori Sakiyama ◽  
Shu Takagi ◽  
Yoichiro Matsumoto
Keyword(s):  
Potential Energy ◽  
Ab Initio ◽  
Multiscale Analysis ◽  
Potential Model ◽  
Research Work ◽  
Pair Potential ◽  
Dynamics Simulation ◽  
Molecular Orbital Calculations ◽  
Ongoing Research ◽  
Trajectory Calculations

We demonstrate the multiscale analysis of the transport phenomena in a low pressure reactor. In this method, the macroscopic phenomena such as the temperature and the density distribution are related to the microscopic electronic structure of atom/molecule. By connecting the different scales with physical models, the macroscopic properties are obtained starting from the first principle calculation without any empirical parameters. Here, we take the silicon epitaxial growth from a gas mixture of silane and hydrogen as an example. As the first step of this method, we calculated the intermolecular potential energy of SiH4/H2 using the ab initio molecular orbital calculations. Then, an analytical pair potential model was constructed to reproduce the potential energy surface obtained from the ab initio calculation. We have confirmed the validation of the potential model by comparing the experimental data of the transport properties with the molecular dynamics simulation using the potential model. Subsequently, the binary molecular collision models were constructed by the classical trajectory calculation using the potential model as the second step of the multiscale analysis. The trajectory calculations were conducted for the various combinations of the initial translational and the rotational energy. Through the statistical analysis of the trajectory calculations, the elastic/inelastic collision cross section and the scattering angle model were constructed. Finally, the direct simulation Monte Carlo simulation of flow field in a low parssure reactor was executed. The thin film thickness distribution was also investigated and discussed. This method was extended to analyze the surface reaction, which is an ongoing research work and only the current progress is reported here.

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