  We present near-infrared spectroscopic analysis of 12 red giant members of
the Galactic open cluster NGC 6940. High-resolution (R$\simeq$45000) and high
signal-to-noise ratio (S/N > 100) near-infrared H and K band spectra were
gathered with the Immersion Grating Infrared Spectrograph (IGRINS) on the 2.7m
Smith Telescope at McDonald Observatory. We obtained abundances of H-burning
(C, N, O), ${\alpha}$ (Mg, Si, S, Ca), light odd-Z (Na, Al, P, K), Fe-group
(Sc, Ti, Cr, Fe, Co, Ni) and neutron-capture (Ce, Nd, Yb) elements. We report
the abundances of S, P, K, Ce, and Yb in NGC 6940 for the first time. Many OH
and CN features in the H band were used to obtain O and N abundances. C
abundances were measured from four different features: CO molecular lines in
the K band, high excitation C I lines present in both near-infrared and
optical, CH and $C_2$ bands in the optical region. We have also determined
$^{12}C/^{13}C$ ratios from the R-branch band heads of first overtone (2-0) and
(3-1) $^{12}CO$ (2-0) $^{13}CO$ lines near 23440
$\overset{\lower.5em\circ}{\mathrm{A}}$ and (3-1) $^{13}CO$ lines at about
23730 $\overset{\lower.5em\circ}{\mathrm{A}}$. We have also investigated the HF
feature at 23358.3 $\overset{\lower.5em\circ}{\mathrm{A}}$, finding solar
fluorine abundances without ruling out a slight enhancement. For some elements
(such as the ${\alpha}$ group), IGRINS data yield more internally
self-consistent abundances. We also revisited the CMD of NGC 6940 by
determining the most probable cluster members using Gaia DR2. Finally, we
applied Victoria isochrones and MESA models in order to refine our estimates of
the evolutionary stages of our targets.
