# Polymer chain simulation with FENE and LJ potential in NVT ensemble

# Initialization

units lj # Use LJ units

atom_style bond # Atoms and bonds

boundary p p p # Periodic boundary conditions in all directions

# Simulation settings

timestep 0.0005 # Timestep size

dimension 3 # 3D simulation

neighbor 0.3 bin # Neighbor list

neigh_modify delay 5 # Modify neighbor list

# Create polymer chain

read_data polymer.data # Load initial polymer chain configuration

# Define potential

pair_style lj/cut 2.5 # Lennard-Jones potential with cutoff 2.5

pair_coeff * * 1.0 1.0 2.5 # Coefficients for all atoms: epsilon, sigma, cutoff

bond_style fene # FENE potential for bonds

bond_coeff 1 30.0 1.5 1.0 1.0 # Coefficients for bonds: K, R0, epsilon, sigma

# Define group for polymer chain

group polymer type 1

# Define compute for center of mass and radius of gyration

# Define compute for center of mass and radius of gyration

compute com polymer com # Compute center of mass

compute gyr polymer gyration # Compute radius of gyration

# Define thermo output

thermo_style custom step temp etotal press c_com[1] c_com[2] c_com[3] c_gyr[1] # Custom output format

thermo 100 # Output thermo information every 100 timesteps

# Output files for center of mass and radius of gyration

fix output_com polymer ave/time 100 1 100 c_com[1] c_com[2] c_com[3] file com.dat

fix output_gyr polymer ave/time 100 1 100 c_gyr[1] file gyration.dat

# Integrator settings

fix nvt polymer nvt temp 1.0 1.0 100.0 # NVT ensemble with temperature control

# Run the simulation

run 10000 # Run the simulation for 10000 timesteps

what is the potential cause for the error,here im attaching the input data file