Hey Dr. Ravikumar, Thank you very much for spreading knowledge. I am really learning from your lectures. Respected Dr. I observed that the LUMO energies are all positive values and that has kept me wondering. Before now, I thought both HOMO and LUMO should be negative. Could you please explain why the LUMO values are positive , thank you very much
Thanks for your support and valuable feedback. When we observe positive energies for filled orbitals it actually means that the electron prefers to go away., if LUMO energy is positive, it means that it costs energy to bind an extra electron to your molecule. This is called Negative Electron Affinity. To correct LUMO energy we should use a larger than minimal basisset. Often our LUMO energy would comes down when extra polarisation and diffuse function are included in the calculation.
thank you for your video. could i ask some questions? I am trying to calculate energy level of compounds to illustrate energy pathway. in this situation, s1, t1 energy level would be absorption wavelength? or I can calculate using gaussian? and when i calculate doublet state, D0, D1, D2 of the compounds how i can set up? what is the difference of s1, t1, lumo and homo? is it possible to regard t1 as lumo? so sorry for many questions. i will be very happy if you answer my questions. thanks
Good evening dear. I learnt many aspects of computational chemistry so, thank you for providing such a nice tutorial for DFT and all. I have little query regarding absorption and emission spectra. If I want to calculate absorption and emission spectra without doing geometry optimization, I mean keeping geometry fixed which I provide to the program. Is that possible?? And if yes, what should we do to do that?? I am waiting for your valuable replay. Thanks Sincerely, Shravan
thank you for your good tutorial.. it is very useful for beginner like me.. in here I want to ask you, how we determine the electron multiplicity for nitro compound, for example nitro methane?
Hello doctor, thank you for making this very helpful video. I have a question, I have no access to checkpoint files but I have TD-DFT output files can I use the generate checkpoint option to produce the FMO diagram with the same accuracy as the loaded checkpoint files? Thank you.
Hey Dr Ravikumar ,thank you for your video, i need to Know how i get Homo lumo energy gap , lattice constant and work function it will be very helpful.
Congratulations on the tutorial. Very didactic. When I went through these steps, the following message was displayed: CConnectionGFCHK::ReadFile() Cannot find file. How to fix?
I've been seeing your videos from last 1 month, as I've very little knowledge of DFT I'm trying to understand things fast which is not good. Can you please help where from I must start and what configuration of my system PC should be used. Any referal vedios?
Thanks a lot Dr! May I ask how do we get the major orbital contribution HOMO -> LUMO in percentage value? I usually read in papers that they will report the orbital contribution transition alongside. Do we need to perform NBO analysis?
Good evening sir, what have to be done when it shows error missing or bad data: alpha orbital energies line number 872 on opening.chk file? .log file is opening without any error
Hello Sir, Thank you for this lecture. After DFT calculation , when I tried to study the HOMO and LUMO , I have got an error message. It was written like this" CConnectionGFCHK::Parse_GFCHK() Missing or bad data:Alpha Orbital Energies Line Number 1144".
