  An equation for the quasi-static soliton ansatz depending on an arbitrary set
of collective variables is covariantly derived on the basis of the variational
approach to the method of collective variables. The field configuration and the
static stresses of the deformed $\Phi ^4$-kink that are produced by the
excitation of the internal soliton mode are exactly determined. The kink
interaction potential at large distances is considered for the example of the
nonlinear Klein-Gordon system. A general approach to the problem of exactly
determining the intersoliton potential for the entire set of physically
admissible two-soliton configurations is discussed.
