  In order to study the nucleon-nucleon pairing effects in clustering nuclei,
we formulate a superposed Tohsaki-Horiuchi-Schuck-Roepke (THSR) wave function,
which includes both molecular-orbit and pairing configurations explicitly. With
this new wave function, we investigate the abnormal deuteron-like pn-pairing
effect in 10B with T=0 and S=1 (isoscalar) by comparing with isovector NN pairs
(T=1, S=1) in 10Be and 10C. Energies are calculated for the ground states of
10Be, 10B and 10C nuclei, and the 1+ excited state of 10B. These energies are
essentially improved comparing with studies using previous version of THSR wave
function. Further more, overlaps between the total wave function and the
pairing component indicate that the NN pairing effect is more visible in 10B
than in 10Be and 10C. By analyzing the energies and the overlaps between wave
function components, we observe two different mechanisms enhancing the
formation of deuteron-like pairs in 10B. We also discuss the pairing effect by
showing average distances between components in each nucleus and density
distributions of valance nucleons.
