Turn one molecule

Two molecule experiment · centres held still

Preparing the sample…

Drag molecule B, or use its angle control.

Model time0.00 ps

Pair interaction—

MD rate

Controls

Arrange two molecules

The planar view is a deliberate teaching slice. Both molecular axes stay in one plane so the orientation change is easy to follow.

Drag either molecule, or use the controls below.

Separation 4.30 ÅAngle A 25°Angle B −50°

Hold the centres still Hold the orientations

Editing prepares the isolated pair at rest. In Free 3D, drag sideways to change azimuth and up/down to tilt the bond towards or away from you. “3D tumble” adds a visible rotational kick; it is an intervention, not a heat bath.

Start with a sample

Number of molecules

The same molecules can heat, cool, translate and rotate. The periodic box has no walls or gravity.

Select a molecule in the whole sample to choose a nearby pair.

Surroundings temperature Heat bath on

180K

50 K450 K

Heat bath on

Translation — K · rotation — K

Real HCl at about 1 atm: melts ~159 K (−114 °C), boils ~188 K (−85 °C). Critical temperature ~325 K.

Reference values only. This finite simulation keeps its volume fixed.

Scientific level

Orientation changes the interaction

Compare with argon’s fluctuating dipoles →

Show in the scene

Crossed dipole arrows run H → Cl. They use the chemistry convention; force arrows are separate.

Average the density illustration

Ordering experiments

The seed uses a symmetry-constrained model trial. Growth beyond its coloured molecules is an experiment, not a validated result.

No seed present.

Waiting target

Monte Carlo equilibration

Try translations and rotations with the same potential. These moves have no physical timescale. The picosecond clock pauses; returning to MD draws fresh thermal velocities.

Physics diagnostics

Waiting for a sample.

Visibility

Label sizeArrow thickness

Fine tune colours

HydrogenChlorineArrowsBackgroundSeed tint