  The multinucleon transfer (MNT) reaction approach was successfully employed
for the first time to measure the isomeric ratios (IRs) of $^{211}$Po
(25/2$^+$) isomer and its (9/2$^+$) ground state at the IGISOL facility using a
945 MeV $^{136}$Xe beam impinged on $^{209}$Bi and $^{\rm nat}$Pb targets. The
dominant production of isomers compared to the corresponding ground states was
consistently revealed in the $\alpha$-decay spectra. Deduced IR of $^{211}$Po
populated through the $^{136}$Xe+$^{\rm nat}$Pb reaction was found to enhance
$\approx$1.8-times than observed for $^{136}$Xe+$^{209}$Bi. State-of-the-art
Langevin-type model calculations have been utilized to estimate the spin
distribution of an MNT residue. The computations qualitatively corroborate with
the considerable increase in IRs of $^{211}$Po produced from $^{136}$Xe+$^{\rm
nat}$Pb compared to $^{136}$Xe+$^{209}$Bi. Theoretical investigations indicate
a weak influence of target spin on IRs. The enhancement of the $^{211}$Po
isomer in the $^{136}$Xe+$^{\rm nat}$Pb over $^{136}$Xe+$^{209}$Bi can be
attributed to the different proton ($p$)-transfer production routes.
Estimations demonstrate an increment in the angular momentum transfer,
favorable for isomer production, with increasing projectile energy. Comparative
analysis indicates the two entrance channel parameters, projectile mass and
$p$-transfer channels, strongly influencing the population of the high-spin
isomer of $^{211}$Po (25/2$^+$). This is the first experimental and theoretical
investigation on the IRs of nuclei produced via different channels of MNT
reactions, with the latter quantitatively underestimating the former by a
factor of two.
