Part of the solution of the matrix equation of normal coordinate analysis, $\mathit{G}\mathit{F}\mathit{L}=\mathit{L}\mathit{\lambda }$. Each element $L_{ik}$ of $\mathit{L}$ is a vibrational eigenvector, and gives the change in internal coordinate $R_i$ during unit change in the normal coordinate $Q_k$, as shown in matrix form by
 $\mathit{R}=\mathit{L}\mathit{Q}$, i.e., $L_{ik}=\partial R_i/\partial Q_k$.

Eigenvectors are sometimes expressed in terms of symmetry coordinates or Cartesian coordinates.