The Completed SDSS-IV extended Baryon Oscillation Spectroscopic Survey:
  Growth rate of structure measurement from anisotropic clustering analysis in
  configuration space between redshift 0.6 and 1.1 for the Emission Line Galaxy
  sample
  We present the anisotropic clustering of emission line galaxies (ELGs) from
the Sloan Digital Sky Survey IV (SDSS-IV) extended Baryon Oscillation
Spectroscopic Survey (eBOSS) Data Release 16 (DR16). Our sample is composed of
173,736 ELGs covering an area of 1170 deg$^2$ over the redshift range $0.6 \leq
z \leq 1.1$. We use the Convolution Lagrangian Perturbation Theory in addition
to the Gaussian Streaming Redshift-Space Distortions to model the Legendre
multipoles of the anisotropic correlation function. We show that the eBOSS ELG
correlation function measurement is affected by the contribution of a radial
integral constraint that needs to be modelled to avoid biased results. To
mitigate the effect from unknown angular systematics, we adopt a modified
correlation function estimator that cancels out the angular modes from the
clustering. At the effective redshift, $z_{\rm eff}=0.85$, including
statistical and systematical uncertainties, we measure the linear growth rate
of structure $f\sigma_8(z_{\rm eff}) = 0.35\pm0.10$, the Hubble distance
$D_H(z_{\rm eff})/r_{\rm drag} = 19.1^{+1.9}_{-2.1}$ and the comoving angular
diameter distance $D_M(z_{\rm eff})/r_{\rm drag} = 19.9\pm1.0$. These results
are in agreement with the Fourier space analysis, leading to consensus values
of: $f\sigma_8(z_{\rm eff}) = 0.315\pm0.095$, $D_H(z_{\rm eff})/r_{\rm drag} =
19.6^{+2.2}_{-2.1}$ and $D_M(z_{\rm eff})/r_{\rm drag} = 19.5\pm1.0$,
consistent with $\Lambda$CDM model predictions with Planck parameters.
