  We find a unitary operator which asymptotically diagonalizes the
Tomonaga-Luttinger hamiltonian of one-dimensional spinless electrons. The
operator performs a Bogoliubov rotation in the space of electron-hole pairs. If
bare interaction of the physical electrons is sufficiently small this
transformation maps the original Tomonaga-Luttinger system on a system of free
fermionic quasiparticles. Our representation is useful when the electron
dispersion deviates from linear form. For such situation we obtain
non-perturbative results for the electron gas free energy and the
density-density propagator.
