  Cosmic rays (CRs) are thought to be accelerated in SNRs. The most favorable
situation for proving that the main, hadronic CR component is accelerated there
is when CRs interact with dense gases, such as molecular clouds (MC) which
surround the SN shock. Here, a new mechanism of spectrum formation in partially
ionized gases near SNRs is proposed. Using an analytic model of nonlinear
diffusive shock acceleration, we calculate the spectra of protons and estimate
the resulting $\gamma$-ray emission occurring when the SNR shock approaches a
MC. We show that the spectrum develops a break in the TeV range and that its
GeV component is suppressed. These modifications to the standard theory occur
because of the proximity of the partially ionized MC-gas and because of the
physics of particle and Alfven wave propagation inside the gas. Possible
applications of the new spectra to the recent CANGAROO and HESS observations of
the SNR RX J1713.7-3946 are discussed.
