The v = 0 - 0 spectrum of H2
Ground-state rotational parameters for molecular hydrogen are evaluated using a combination of laboratory and observational data. High-accuracy v = 0 - 0 S(0)-S(5) frequencies from infrared laboratory measurements are analyzed simultaneously with available observed frequencies for the S(8), S(9), S(12), S(13), S(14), and S(15) Orion emission lines. The laboratory and Orion measurements are consistent with each other within their measurement errors. The combined data set yields a determination of five v = 0 rotational parameters and an improvement in the high-J calculated line positions. The analysis produces the parameters (in per cm): B(0) = 59.334627(30), D(0) = 0.0456912(30), H(0) = 4.8974(90) x 10 to the -5th, L(0) = -6.320(110) x 10 to the -8th, M(0) = 7.19(30) x 10 to the -11th, where a correction is made for the estimated contribution of sixth and higher orders.