GROMACS version:2022.2
GROMACS modification: Yes/No
With the intent of obtaining a representation of an IR spectrum, I have set up a simple unconstrained model of short PVC molecules in vacuum under single precision in npt with dt = 0.0001 ns , 100000 steps. ff gromos 54A7 ( yes I know… ) I am assuming the velocity correlation function takes q into account. I can obtain a spectrum in cm -1 using velacc with the os option, but it spans only 1 to 600 cm-1, I was hoping to see wavenumbers to about 4000 cm-1.
Must the model be run under double precision ? Do I need to create a q*v file for input ? Is the ff inappropriate ? Is it even possible to obtain IR spectra with velacc ?
Regards.
pb