Microwave spectrum, structure, and dipole moment of sulfuric acid

The microwave spectra of the normal, ³⁴S, D₁ and D₂ isotopic species of gaseous sulfuric acid have been assigned. Rotational and centrifugal distortion constants were obtained. A conformation with C₂ symmetry has been identified. Important structural parameters are r(OH) = 0.97(1) \, r(SO₁) = 1.574(10) \, r(SO₂) = 1.422(10) \, < H₁0₁S = 108.5(15)\∘, < 0₁SO₁, = 101.3(10)\∘. < 0₂SO₂, = 123.3(10)\∘. The torsional angle O₁’sO₁H is -90.9(10)\∘ and the two SO₂ planes form an angle of 88.4(1)\∘. The dipole moment was determined to be 2.725(15) Debye.