Hi,
I am conducting a UV-Vis spectral study on nanoclusters using Gaussian. Can anyone guide me on how to obtain the UV-Vis spectrum plotted as photon energy (eV) versus intensity (a.u.)?
I am performing TD-DFT calculations for this purpose. However, when I plot the graph between photon energy (eV) and intensity (a.u., which is proportional to the oscillator strength), I observe only one prominent peak. The smaller peaks representing different transitions between HOMO and LUMO levels, commonly seen in literature, are absent. ( as shown in Figure 4 of following literature doi.org/10.1002/anie.202410109)
How can I generate a spectrum that clearly shows these distinct smaller peaks corresponding to various transitions? Any guidance or suggestions would be greatly appreciated.
What you get from the calculation is only the energy gap of different energy levels of the cluster. GView will give a plot by recalculate the peak function from the energy and intensity. The recalculation has many parameters to adjust, like half wave width. Here, the energy levels are still there, question is that when you obtain the spectrum, nearly everything is hidden by the highest peak. You can redraw the spectrum by setting different parament according your system properities.
Sihan Zhang Thank you very much.
Can I do these settings, like UV-Vis Peak Half-Width at Half Height that corresponds to FWHM, in Gaussview? I am using Gaussview to draw the UV-VIS Spectrum.
How can I determine the optical band gap from the UV-Vis spectrum? Is the optical band gap equivalent to the energy of the excited state with the highest frequency? Could you please advise on the correct approach to identify the optical band gap?
Best,
Beenish Ajmal.
For the first question, yes, it is in plots->properities->plot, default value is 0.333 eV.
For the second one, I cannot provide too much help. It is better to refer some papers in your area.
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