Hi, dear bro Please provide a video demonstrating how to create HOMO and LUMO using VMD. We are looking forward to hearing back from you regarding this tutorial.
Hi there! Thanks for the suggestion, I will consider making a tutorial with VMD as it's a great package, espically if you work with very large molecules, like proteins. IboView can also be used to visualize HOMO and LOMOs, as well as localized molecular orbitals. I have a video on my channel if you're interested. All the best :)
Nice! I'm really glad to hear it. I'm very curious, what kind of homework do you have? Undergraduate, master level, high school? And what is the assignment? if you don't mind me asking.
Hi there! It's cool to hear you'd like to see some more content :) I do have another video in the works, but getting it finished has taken much longer than I would have liked. Balancing my research and my content creation has been tough, entering the 4th and final year of my phd now, but I promise it's on the way :)
I need in your help. I want to calculate dissociation energy of molecule N2. I use Hartry-Focks method and try 10 basis: qzvp, svp, sv(p), tzvp, sto-3g, 3-21g, 4-22gsp, 6-31g, sv, tzv and all of them give me wrong result. I calculate by formula: energy of dissociatian = energy(N2) - 2*energy(N). With this basis I get energy dissociation about -5eV - 0.5eV, but the true value is equal to 9.76eV. What do I do wrong?
Hello. Thanks for your question! Looking through your calculations with HF + a series of basis sets, you should see some interesting trends. In particular, the larger the basis set, the lower the energy (for any one system). This is because HF is variational. However, even in the limit of a complete basis set, HF will still give you the wrong result. This is because HF does not properly treating the correlation between electrons. In fact, formally speaking, the correlation energy is defined as the difference between the HF energy and the exact (FCI) energy. Since the correlation energy increase with the number of electrons, the error by not including it is larger in energy(N2) vs. 2*energy(N), and this is why these kinds of dissociation energies calculated with HF will always be wrong. To obtain (more) accurate values, you should use a correlated method e.g. configuration interaction (CI), coupled cluster (CC), or the complete active space self-consistent field (CASSCF) method. Does that help? :)
@@TheBondChem yes, thank you, I did it. I use CASSCF method with nept2 with basis QZVPP. I got 9.63744 eV. The experimental result of dissociation energy(N2) = 9.67 eV.
I want to measure the nature vibration( natural frequency) of one of the amino acids of a molecule. in your opinion what shall I do? by which software I can calculate it?
You can use the Opt Freq keywords in an ORCA input to calculate the (natural) vibrational modes of a molecule. For amino acid, you should be able to get accurate numbers fairly easy. I'd recommend the 3c methods e.g. HF-3c, PBEh-3c or r2SCAN-3c. For more info see: sites.google.com/site/orcainputlibrary/vibrational-frequencies-thermochemistry
Hello, sure :) It's unlikely I will make a video dedicated to installation as I'd prefer my channel to focus more on the chemistry itself but, in addition to the links in the description, you can check out this page from the ORCA forum for a set-up guide: sites.google.com/site/orcainputlibrary/setting-up-orca
Hello Pratap :) Set up on the m1 should be the same as other mac systems. You can find more here: sites.google.com/site/orcainputlibrary/setting-up-orca
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