Highly excited rovibrational states of HNC

► HNC 1463 K hot gas molecular emission spectroscopy, 51 HNC rovibronic (ν1, ν2, l, e/f, ν3) substates characterized for the first time. ► 0ν2l1→0ν2l0 bands up to ν2=7,0ν2l2→0ν2l1 bands up to ν2 = 4 and 2ν2l0→0ν2l0 bands up to ν2 = 4. ► Vibrational expansion coefficients of the spectroscopic constants for 94 HNC rovibrational states.