[en] A detailed low-energy level scheme of the odd-odd n-rich nucleus _7_3"1"8"4Ta_1_1_1 is constructed using the well tested Two-Quasiparticle Rotor Model (TQRM) for calculating the bandhead energies of physically admissible 2qp configurations with the inclusion of residual n-p interaction contribution. The presently available data on this level scheme from "1"8"4Hf decay are shown to be in agreement with these calculations. Our analysis concludes that "1"8"4Hf (Q_β = 1340(30) keV) decay admits of 7 additional (to the 3 presently reported) β -branches to "1"8"4Ta with J = 0 or 1 and 8 more physically admissible weak (1f"u) β -branches populating J"π = 2"- levels in "1"8"4Ta. Further, a close examination of our level scheme clearly indicates the existence of a low-lying (E_x = 260(40) keV) high-spin (J"π = 10"-) long-lived isomer in this nucleus. (orig.)