Collisional excitation of HC3N by para- and ortho-H2
  New calculations for rotational excitation of cyanoacetylene by collisions
with hydrogen molecules are performed to include the lowest 38 rotational
levels of HC3N and kinetic temperatures to 300 K. Calculations are based on the
interaction potential of Wernli et al. A&A, 464, 1147 (2007) whose accuracy is
checked against spectroscopic measurements of the HC3N-H2 complex. The quantum
coupled-channel approach is employed and complemented by quasi-classical
trajectory calculations. Rate coefficients for ortho-H2 are provided for the
first time. Hyperfine resolved rate coefficients are also deduced. Collisional
propensity rules are discussed and comparisons between quantum and classical
rate coefficients are presented. This collisional data should prove useful in
interpreting HC3N observations in the cold and warm ISM, as well as in
protoplanetary disks.
