Molecular reorientation cross sections in collisions of He([sup 1][ital S])+D[sub 2]([ital B] [sup 1][Sigma][sup +][sub [ital u]]), HD([ital B] [sup 1][Sigma][sup +][sub [ital u]])

Reorientation cross sections for He--D[sub 2]([ital B]) and He--HD([ital B]) are reported for the energy range of 0.302[times]10[sup [minus]3]--0.300 eV. The single surface scattering model and coupled-channel method used for the He--H[sub 2]([ital B]) [J. Chem. Phys. [bold 99], 2632 (1993)] are also used for these systems. At 295 K the calculated reorientation cross section for He--D[sub 2]([ital B]) is 45.4 A[sup 2] and the Boltzmann average is 39.5 A[sup 2]. The Boltzmann average value is to be compared with the measurement by Pibel and Moore of 27.6[plus minus]10.8 A[sup 2] [J. Chem. Phys. [bold 93], 4804 (1990)]. The corresponding cross section calculated for He--HD([ital B]) is 29.5 A[sup 2] and the Boltzmann average is 29.3 A[sup 2]. The latter is in good agreement with the experimental determination of 33.2[plus minus]5.0 A[sup 2]. Because of the rotational transition that is open for the HD target, many more open channels had to be considered to achieve convergence compared to the H[sub 2] and D[sub 2] targets.