I want to calculate ACF of radius of gyration using gmx gyrate. I used the following command:
gmx gyrate -f npt3.xtc -s npt3.tpr -o gyrate.xvg -acf gyrateacf.xvg -n molindex.ndx -b 0 -e 50000
and it gave the the plot like I attached here. First, I asked for 0 to 50000 (ps) but it gave me 0 to 2500 (ps). Why?
second. I asked for just polymer molecule ACF of Rg but there are three plots. I can not distinguish that plots. Which plot can be used for polymer ACF of Rg?