Working with Trajectories

This tutorial shows how to visualize molecular dynamics trajectories.

Opening Trajectory Files

Supported Formats

Format	Extension	Description
VASP XDATCAR	XDATCAR, .xdatcar	VASP MD trajectory
Multi-frame XYZ	.xyz	XYZ with multiple frames
VASP OUTCAR	OUTCAR, .outcar	VASP output with ionic steps
QE Output	.out, .pwo, .log	QE output with ATOMIC_POSITIONS blocks
CASTEP Output	.castep	CASTEP geometry optimization/MD

Open a Trajectory

1. Open the trajectory file in VS Code
2. ACoord detects multiple frames
3. The Trajectory panel appears
4. First frame loads automatically

Trajectory Panel

Playback Controls

Button	Action
|<	Go to first frame
<	Previous frame
Play	Play animation
>	Next frame
>|	Go to last frame

Frame Navigation

• Enter frame number in the input box and press Enter
• Or use Previous/Next buttons

Playback Speed

• Use the Speed slider (1-30 fps)
• Higher = faster playback

Analyzing Trajectories

Track Atom Movement

1. Select an atom in the first frame
2. Play the trajectory
3. Selection persists across frames

Measure Bond Evolution

1. Select two atoms
2. Play the trajectory
3. Distance updates each frame

Exporting Frames

Export Current Frame

1. Navigate to desired frame
2. Click Save As button in toolbar
3. Choose format (POSCAR, XYZ, etc.)

Export HD Image

1. Navigate to desired frame
2. Click the Export button in toolbar