Abstract: | The 2ν3(A1) band of 12CD3F near 5.06 μm has been recorded with a resolution of 20–24 × 10−3 cm−1. The value of the parameter (αB − αA) for this band was found to be very small and, therefore, the K structure of the R(J) and P(J) manifolds was unresolved for J < 15 and only partially resolved for larger J values. The band was analyzed using standard techniques and values for the following constants determined: ν0 = 1977.178(3) cm−1, B″ = 0.68216(9) cm−1, D″J = 1.10(30) × 10−6 cm−1, αB = (B″ − B′) = 3.086(7) × 10−3 cm−1, and βJ = (D″J − D′J) = −3.24(11) × 10−7 cm−1. A value of αA = (A″ − A′) = 2.90(5) × 10−3 cm−1 has been obtained through band contour simulations of the R(J) and P(J) multiplets. |