I designed a sensor based on the interactions between the analyte and carbon dots (CDs). I obtained the experimental data including FT-IR, absorption and fluorescence spectra of CDs, and analytical parameters (LOD, LOQ, LDR, RR). According to the obtained experimental data, I suggested a sensing mechanism.
Now, I'm going to study the sensing mechanism by density functional theory. There are a lot of papers that utilize various structures as the optimum structure of CDs in Gaussian. I don't know which structure should be considered for my carbon dots? could someone help me, please?
Mrs/Miss Manshaei,
With GaussView there is unable to do theoretical prediction of any kind of parameters. It can be used to prepare your inpur files for computation by Gaussian (https://gaussian.com/.) The latter program-package is a powerful tool for such purposes, amongst others, quantum chemical programs.
Dear Faranak,
Unfortunately, there is no quick answer for your problem. The properties of any material (and specially a 3D material) change A LOT with its structure, size, defects... thus you cannot take just the structure you like and go with it.
That being said, I think you can take two routes. Assuming that you have prepared your CDs in a specific way, you should search in the bibliography which structure arises from that synthetic route or the closest route for the one you have developed (temperature, pH, reagents...). The other option, given that you have a sizable amount of experimental data (FTIR, UV-vis absorption...) is to take several structures and calculate these properties for each of them, and then choose the structure whose results are closer to the experimental ones. Before that, you will have to investigate which is the best DFT functional for this kind of systems.
As a final remark, I'm not sure if Gaussian is the best package you can use. Even for non-infinite materials, it is usually better to work with codes able to proficiently deal with periodic boundary conditions (such as VASP), as the convergence of plane waves for large materials is much faster than with atom-centered Gaussian basis sets. If you don't have access to these codes, then forget about it and go with the Gaussian package.
Hope you find it helpful.
Enrique Manuel Arpa
Dear Enrique
Thanks for your constructive comments.
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