  The energies and decay widths of the states of the exotic 7He nucleus are
studied in an ab initio approach. The spectrum of these states is calculated
using No-Core Shell Model and corresponding extrapolation procedure.
Well-proven on a large amount of data the Daejeon16 potential is used in the
calculations. The previously developed NCSM-based approach, which includes a
method for constructing the basis of orthogonalized functions of cluster
channels and a procedure for matching the cluster form factors obtained within
this method with the corresponding asymptotic wave functions, is applied to
compute the decay widths of the levels. The possibilities of the approach for
calculating the partial decay widths of nuclear states into various channels
strongly differing in type of fragmentation, spin, angular momentum of relative
motion, and amplitude are demonstrated. The results obtained are compared with
the results of other microscopic calculations.
