Terahertz Vibrational Molecular Clock with Systematic Uncertainty at the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msup><mml:mn>10</mml:mn><mml:mrow><mml:mo>−</mml:mo><mml:mn>14</mml:mn></mml:mrow></mml:msup></mml:math> Level

Neutral quantum absorbers in optical lattices have emerged as a leading platform for achieving clocks with exquisite spectroscopic resolution. However, the studies of these and their systematic shifts so far been limited to atoms. Here, we extend this architecture an ensemble diatomic molecules experimentally realize accurate lattice clock based on pure molecular vibration. We evaluate systematics, including characterization nonlinear trap-induced light shifts, total uncertainty $4.6\times10^{-14}$. The absolute frequency vibrational splitting is measured be 31 825 183 207 592.8(5.1) Hz, enabling dissociation energy our molecule determined record accuracy. Our results represent important milestone spectroscopy THz-frequency standards, may generalized other neutral species applications fundamental physics, tests electrodynamics search new interactions.