Weakly bound complexes trapped in quantum matrices: Structure, energetics, and isomer coexistence in...

The ground state of mixed (para-H(2))(N)(ortho-D(2))(3) clusters of sizes ranging from N=8 to 37 is examined by means of the path integral ground state method. The chemical potential is calculated and reveals that magic numbers are consistent with those found in pure para-H(2) and ortho-D(2) clusters. The structural features of the mixed clusters are examined by analyzing density profiles, one-dimensional Pekeris distribution functions of the (ortho-D(2))(3) subsystem, and by direct visualization of density isosurfaces of the systems. The heavier (ortho-D(2))(3) complex resides in the center of the cluster for the various sizes under consideration. It is found that certain cluster sizes favor either equilateral, or near-linear isosceles (ortho-D(2))(3) configurations, while others show a coexistence between those two triangular geometries.