Account of proton channel coupling in the optical-shell description of relaxation widths of isobaric analog resonances

The method for calculating relaxation widths (GITA) of the isobaric analog resonances (IAR) in intermediate and heavy nuclei is considered. A quantitative interpretation of the widths GITA is proposed based on a pumerical solutiop of the iptegral equation for effective coulomb field with account of the O+-state coupling of the proton-neutron hole state both to the continium and multiparticle configurations. As example the widths GITA are calculated for the decay of IAR excited following the proton scattering on the 207Pb, 140Ce, 138Ba and 90Zr nuclei. The results of the width GITA calculation for the nuclei mentioned are tabulated. The foltowing conclusions are drawn: the account of the channel coupling results in a substantial decrease in the calculated GITA values; the GITA values practically are independent of the optical shift; satisfactory agreement of the calculated and experimental GITA values can be attained at the same values of the optical model parameters that are used for the description of the E1-total widths and the Ga, mow-Teller giant resonances as well as partial proton IAR's widths