Onset of collectivity in the odd-odd nucleusAs72

High-spin states in the odd-odd nucleus ${}_{}{}^{72}{}_{}{}^{}\mathrm{As}$ were investigated by means of coincidence measurements via the ${}_{}{}^{59}{}_{}{}^{}\mathrm{Co}$ ${(}^{19}$F,αpn) and the ${}_{}{}^{65}{}_{}{}^{}\mathrm{Cu}$ ${(}^{12}$C,αn) reactions at beam energies of 55 MeV and 50 MeV, respectively. Two new rotational-like level sequences of probably opposite parities have been found to feed into the known $7^{\left(\mathrm{-}\right)}$ isomer at 562.8 keV. Lifetime measurements for some states of the positive-parity sequence using the Doppler shift attenuation method revealed transition strengths of B(E2)≊40 Weisskopf units. Thus, this band is interpreted as a collective structure built on the two-quasiparticle intruder configuration (π${\mathit{g}}_{9/2}$⊗ν${\mathit{g}}_{9/2}$).