Reinvestigation of the CO A1Π state and its perturbations: The v = 0 level

Reanalysis of the Ångström System (B1Σ+- A1Π) in the13C16O Isotopic Molecule

“…The most comprehensive analysis and deperturbation calculation on the basis of the data obtained up to 1971 was performed by Field [35] and Field et al [38]. Le Floch et al [40] conducted an extensive study of the A 1 Π (υ = 0) state perturbation. Le Floch [41] There have been comparatively few explorations of the A 1 Π perturbations in 13 C 16 O isotopologue.…”

Perturbations in the A1Π,v= 0 state of12C18O investigated via complementary spectroscopic techniques

“…We do not experimentally observe spectral lines associated with D(0) nor I(1) and their avoided crossings with A(0) occur above our highest-observed J level. Fixed molecular constants representing the D(0) and I(1) levels are nevertheless included in our perturbation analysis by isotopically rescaling their electronic-state equilibrium constants found in the literature [52][53][54][55] [50] (parameter b in their Table IV). A similar mass-scaling calculation is described by Hakalla [30].…”

VIS and VUV spectroscopy of 12C17O and deperturbation analysis of the A1Π, υ = 1–5 levels

“…The assignment of perturber levels, the selection of which parameters and interactions could be discriminated from our spectra, and the values of these parameters were iteratively optimised. The Pgopher program 67 uses the effective Hamiltonian with matrix elements similar to Field, 30 Bergeman et al, 84 and Le Floch et al 31 The model is presented in The unweighted obs-calc residuals of the tting method are dominated by the uncertainties of the very weak and heavily perturbed lines that belong to the weakest B-A (1, 1) and (1,5) bands. The weighted contribution to the root-mean-square (rms) residual value of high-accuracy dispersive optical spectroscopy and VUV-FTS data is 0.006 cm…”

“…is then possible to calculate initial values of interaction parameters for any pair of levels whenever the relevant vibrational wavefunctions are known. 31 So, the missing perturbation parameters, which were xed during the deperturbation calculation, were estimated on the basis of the isotopologueindependent purely electronic perturbation parameters a and b of Le Floch, 31 as well as hy A |y d,e,or a 0 i vibrational overlap integrals and the hy A |B(R)|y I or D i rotational operator integral in 12 C 17 O, according to eqn (1)- (8). These parameters are presented in Table 9.…”