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Viewer: draw the polarizability tensor as an ellipsoid #279
Description
Since 1d7b8d1 (#266) the Quadrupole, Polarizability, Hyperpolarizability and Stress panels show only their tables; the three principal-axis arrows they drew suggested a vector and could not show a negative eigenvalue.
For the polarizability a picture is meaningful: the tensor is symmetric with positive eigenvalues, and its principal axes are the directions in which the electron cloud is easiest and hardest to distort.
Proposed
- Polarizability panel: a translucent ellipsoid at the centre of nuclear charge, semi-axes along the eigenvectors, proportional to the eigenvalues, with a scale control as in the Dipole panel. The panel states the scale (Å per a.u. or per ų) and lists the eigenvalues and the isotropic mean α = (α₁+α₂+α₃)/3.
- Quadrupole, Hyperpolarizability and Stress keep the table only.
- Checked for at least two codes that print the polarizability tensor (e.g. ORCA, Gaussian 16), with a headless render.
Activity
Draw the polarizability tensor as an ellipsoid in the viewer (#279)
ohlincha commentedon Oct 11, 2026
41e4bc6: the Polarizability panel draws a translucent ellipsoid at the centre of nuclear charge, semi-axes along the eigenvectors of the symmetrised tensor and proportional to the eigenvalues (default: longest semi-axis 1.5 Å; size slider in Å per 10 a.u.), and lists the principal values (a.u. = bohr³), the isotropic mean and the semi-axes in Å. Quadrupole, Hyperpolarizability and Stress show the table only. Checked headless against real Gaussian 16 outputs (water, CO2, benzene; parsed by the real parser): CO2's long axis lies along the molecule (23.76 / 8.50 / 8.50), benzene's in-plane values are equal (75.13) and larger than the out-of-plane one (40.91). ORCA prints the tensor with %elprop Polar 1, but ECCE does not request or parse it yet; the ORCA check used values copied from the output. To be checked on screen.
Polarizability ellipsoid: near faces only on a finer mesh, so the tra…
ohlincha commentedon Oct 12, 2026
Checked on screen (Linux): fixed.