Abstract:
Ab initio calculations are performed to
determine new potential energy surfaces for the ground
state and low-lying excited states of C3 induced by collision
with atomic hydrogen. The calculations are performed using
the multireference configuration interaction method including
Davidson’s correction using aug-cc-pVQZ (augmented
correlation consistent polarized valence quadruple zeta)
basis sets. Nonadiabatic effects leading to avoided crossings
are observed between ground and excited states. The
computed points of the ground-state surface are fitted to an
analytical form suitable for time-independent quantum
scattering calculations of the state-to-state collisional cross
sections. The close-coupling calculations are performed up to 1000 cm−1
. Resonances are observed at very low energies. Among
all the rotational transitions, Δj = 2 is found to be predominant for excitation. After Boltzmann thermal averaging collisional
cross sections, rate coefficients for rotational levels j = 0, 2, ..., 8 are obtained and discussed covering the temperature up to 100
K. The magnitude of the state-to-state excitation rate obtained is maximum for j = 0 → 2 transition and decrease for other
higher excitations. The results computed in this work will be crucially required to accurately model the abundance of carbon
trimer and its hydrocarbon form in space.
