  The eigenvectors of the electronic stress tensor have been identified as
useful for the prediction of chemical reactivity because they determine the
most preferred directions to move the bonds that correspond to a qualitative
change in the molecular electronic structure. A new 3-D vector based
interpretation of the chemical bond that we refer to as the bond-path framework
set $\mathbb{B} = \{p,q,r\}$ provides a version of the quantum theory of atoms
in molecules (QTAIM) beyond the minimum definition for bonding that is
particularly suitable for understanding changes in molecular electronic
structure that occur during reactions. The bond-path framework set $\mathbb{B}$
is straightforwardly constructed and visualized from the eigenvalues and
eigenvectors of QTAIM. This approach is applied to the structural deformations
of ethene that occur during applied torsion ${\theta}$, -180.0{\deg} $\leq$
${\theta}$ $\leq$ +180.0{\deg}. The corresponding stress tensor version is
readily constructed as $\mathbb{B}_{\sigma} = \{p_{\sigma},q_{\sigma},r\}$
within the QTAIM partitioning making it possible to compare experimentally and
computationally determined electronic charge densities. The bond-path framework
set $\mathbb{B}$ or $\mathbb{B}_{\sigma}$ are the networks that comprise three
strands: the least preferred ($p, p_{\sigma}$), most preferred ($q,
q_{\sigma}$) and $r$ is the familiar QTAIM bond-path. We demonstrate that the
most preferred direction for bond motion using the stress tensor corresponds to
the most compressible direction and not to the least compressible direction as
previously reported. We show the necessity for a directional approach
constructed using the eigenvectors along the entire bond length and demonstrate
the insufficiency of the sole use of scalar measures for capturing the nature
of the stress tensor within the QTAIM partitioning.
