title: Fundamental vibration of molecular hydrogen.
abstract: The fundamental ground tone vibration of H(2), HD, and D(2) is determined to an accuracy of 2×10(-4) cm(-1) from Doppler-free laser spectroscopy in the collisionless environment of a molecular beam. This rotationless vibrational splitting is derived from the combination difference between electronic excitation from the X(1)Σ(g)(+), v=0, and v=1 levels to a common EF(1)Σ(g)(+), v=0 level. Agreement within 1σ between the experimental result and a full ab initio calculation provides a stringent test of quantum electrodynamics in a chemically bound system.
authors.affiliation: Department of Physics and Astronomy, LaserLaB, VU University, de Boelelaan 1081, 1081HV Amsterdam, The Netherlands.
authors.forename: G D
authors.initials: GD
authors.lastname: Dickenson
authors.forename: M L
authors.initials: ML
authors.lastname: Niu
authors.forename: E J
authors.initials: EJ
authors.lastname: Salumbides
authors.forename: J
authors.initials: J
authors.lastname: Komasa
authors.forename: K S E
authors.initials: KS
authors.lastname: Eikema
authors.forename: K
authors.initials: K
authors.lastname: Pachucki
authors.forename: W
authors.initials: W
authors.lastname: Ubachs