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Modeling environments that are not in local thermal equilibrium, such asprotoplanetary disks or planetary atmospheres, with molecular spectroscopicdata from space telescopes requires knowledge of the rate coefficients ofrovibrationally inelastic molecular collisions. Here, we present such ratecoefficients in a temperature range from 10 to 500 K for collisions of CO$_2$with He atoms in which CO$_2$ is (de)excited in the bend mode. They areobtained from numerically exact coupled-channel (CC) calculations as well asfrom calculations with the less demanding coupled-states approximation (CSA)and the vibrational close-coupling rotational infinite-order sudden (VCC-IOS)method. All of the calculations are based on a newly calculated accurate abinitio four-dimensional CO$_2$-He potential surface including the CO$_2$ bend($\nu_2$) mode. We find that the rovibrationally inelastic collision crosssections and rate coefficients from the CSA and VCC-IOS calculations agree towithin 50% with the CC results at the rotational state-to-state level, exceptfor the smaller ones and in the low energy resonance region, and to within 20%for the overall vibrational quenching rates except for temperatures below 50 Kwhere resonances provide a substantial contribution. Our CC quenching ratesagree with the most recent experimental data within the error bars. We alsocompared our results with data from Clary et al. calculated in the 1980's withthe CSA and VCC-IOS methods and a simple atom-atom model potential based on abinitio Hartree-Fock calculations and found that their cross sections agreefairly well with ours for collision energies above 500 cm$^{-1}$, but that theinclusion of long range attractive dispersion interactions is crucial to obtainreliable cross sections at lower energies and rate coefficients at lowertemperatures.

State-to-state rovibrational transition rates for CO2 in the bend mode in collisions with He atoms