/usr/share/gromacs/top/amber99sb.ff/rna.arn is in gromacs-data 4.5.5-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 | RNA OP1 O1P
RNA OP2 O2P
RNA H2' H2'1
RNA H2'' H2'2
RNA H5' H5'1
RNA H5'' H5'2
RNA HO5' H5T
RNA HO3' H3T
|