Part of the terahertz spectrum of CH₃¹⁷OH showing the A symmetry v_t = 0 K_a = 7 ← 6 Q-branch. Selected J values are indicated. Strong transitions of CH₃¹⁶OH are indicated by their quantum numbers given in black. These are from left to right two blended v_t = 0 and 1 transitions of E symmetry and two v_t = 0 transitions of A symmetry. Weaker transitions of CH₃¹⁶OH are indicated by black x, one weaker transition of CH₃¹⁷OH is denoted by a blue plus sign. Several of the weak or very weak lines remain unassigned at present.