Rotationally inelastic scattering of ND₃with H₂as a probe of the intermolecular potential energy surface

Abstract

General rightsThis document is made available in accordance with publisher policies. Please cite only the published version using the reference above.

Collisional excitation of NH3 by atomic and molecular hydrogen

“…Rate coefficients were deduced for transitions among ammonia levels with j 3 and kinetic temperatures in the range 5-100 K. It should be noted that the accuracy of the NH3-H2 PES of Maret et al (2009) was recently checked against various experiments. In particular, state-to-state resolved DCSs for the inelastic scattering of ND3 with H2 at a collision energy of 580 cm −1 were measured by Tkáč et al (2015) and satisfactorily reproduced by quantal calculations. The isotropic part of the NH3-H2 PES was also probed by the molecular beam experiment of Pirani et al (2013), which has provided a further accuracy assessment by measuring the glory quantum interference structure.…”

Rotational Spectroscopy of the NH3–H2 Molecular Complex

“…-H 2 species were found for H 2 O-H 2 by van der Avoird and Nesbitt (2011). It is also remarkable that D 0 is much smaller than the binding energy D e =267 cm −1 in the potential of Maret et al (2009), which implies that the zero-point energy associated with the intermolecular vibrations and hindered rotations is large.…”

“…The global minimum in the final potential deduced from an analytical fit to all data points has a depth D e of 267cm −1 and corresponds to a structure with intermolecular center-ofmass distance R=3.23 Å and H 2 collinear with the C 3v axis of ammonia at the nitrogen end (see Figure 1). This PES has been employed in studies of collision dynamics of NH 3 with H 2 (Maret et al 2009;Wiesenfeld et al 2011;Pirani et al 2013;Daniel et al 2014;Ma et al 2015;Tkáč et al 2015).…”

“…(1,778,962 MHz), given by Tkáč et al (2015). The atomic masses are 1.007825 u for H and 14.003074 u for 14 N. For the intermolecular center-of-mass distance R, we used a discrete variable representation (DVR) with a grid of 95 equidistant points ranging from R=4 to 26 a 0 .…”

“…The atomic masses are 1.007825 u for H and 14.003074 u for 14 N. For the intermolecular center-of-mass distance R, we used a discrete variable representation (DVR) with a grid of 95 equidistant points ranging from R=4 to 26 a 0 . This DVR basis was contracted into a radial basis of 20 functions constructed in the same way as in van der Avoird and Nesbitt (2011). To represent the hindered rotations of NH 3 and H 2 in the complex, we used a basis of symmetric rotor functions and spherical harmonics, respectively, which was truncated to internal rotor quantum numbers j NH 3 10 and j H 2 6.…”