REU in Physics at Howard University. Raman Spectroscopy and COMSOL Multiphysics Studies of Tungsten Oxide (WO3) as a Potential Metal-Oxide Gas Sensor. Larkin Sayre. Metal-Oxide Gas Sensors (MOGS). The basic principle
REU in Physics at Howard University
Raman Spectroscopy and COMSOL Multiphysics Studies of Tungsten Oxide (WO3) as a Potential Metal-Oxide Gas Sensor
2 main aspects of my project:
Side project – LAMMPS and Molecular Dynamics
The basic principle:
A laser is directed towards the molecule and the scattered light is detected and interpreted.
The sensors must first be calibrated
The sample is placed in a plastic holder
Short test iterations to ensure laser is hitting the sample
Sample of polystyrene used
Examples of peak assignments:
Units are “wavenumber” – 1/wavelength
Raman spectra increasing temperature from 30 Celcius to 190 Celcius.
Raman spectra decreasing temperature from 190 Celcius to 30 Celcius
COMSOL is a CAD modeling software that creates simulations of real-world systems. It is heavily used by researchers and academics and it is a valuable skill for me to pick up during my REU.
The classic simulation example is the busbar with DC current running through it producing Joule heating. This heating can be mapped by COMSOL and displayed as below. The bar section is copper while the pins attached are titanium.
LAMMPS Citation: S. Plimpton, Fast Parallel Algorithms for Short-Range Molecular Dynamics, J Comp Phys, 117, 1-19 (1995), http://lammps.sandia.gov/
lmp_serial.exe < graphene_attempt_2.txt
Produced 108 atoms – no fixes defined, atoms won’t move
Information on computational cost
Software used – VMD and Ovito
Both software packages produce visualizations from the ‘dump’ file created by LAMMPS.
Experimentation with lattice structure using VMD
Raul Garcia and Daniel Casimir
NSF for REU funding
COMSOL Multiphysics for Heat Transfer Simulation Workshop and module trials