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Physical Measurement Laboratory

Hydrocarbon Spectral Database, Table 2.1

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Table 2.1. Determinable rotational and centrifugal distortion constants (P⁴) employed by various workers^a

Kivelson-Wilson Parameters for planar molecules	Kirchhoff parameters (following Watson [15])	Watson parameters [16]
A′	A′′ = A′ - 1/2τ′_bbcc	A
B′	B′′ = B′ - 1/2τ′_aacc	B
C′	C′′ = C′ - 1/2τ′_aabb	C
τ_aaaa	τ_aaaa	Δ_J
τ_bbbb	τ_bbbb	Δ_JK
τ_abab	τ_cccc	Δ_K
τ_aabb	τ₁ = τ′_aabb + τ′_bbcc + τ′_ccaa	δ_J
τ_aabb	τ₂ = (A′ / S) τ′_bbcc + (B′ / S) τ′_aacc + (C′ / S) τ′_aabb	δ_K
^aFor conversion between the various sets of parameters see References [4], [9], [10], and [17].

Analytical chemistry, Atomic / molecular / quantum and Reference data

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Sensor Science Division

Francis J. Lovas

francis.lovas@nist.gov

(301) 975-2385

Created April 23, 2018, Updated November 15, 2019