# Create a monovalent ion in a box of TIP3P water.

# Load AMBER '96 forcefield for protein.
source leaprc.ff96

# Create a container with a single sodium ion.
system = sequence { Na+ }

# Solvate in water box.
solvateBox system TIP3PBOX 10.0 iso

# Check sytem.
check system

# Write parameters.
saveAmberParm system system.prmtop system.crd

# Exit
quit