Quantitative Analysis of Vibration-Rotational Spectra of Diatomic Molecules with (v,j)-Dependent Dynamical Reference Conformation. Application to LiH X¹Σ⁺

Abstract

An extension of deformationally self-consistent approach to a quantitative analysis of adiabatic and nonadiabatic effects in vibration-rotational spectra of diatomic molecules is presented. We consider vibrational displacements of nuclei in the vicinity of dynamical reference conformation R" j that depends not only on the rotational quantum number J through the action of centrifugal force, but also on the vibrational v one, through nonadiabatic vibrational effects of high order. The method is applied to LiH X 1L"±; reported wave numbers of transitions are reproduced with 3 =

The inversion of diatomic Born–Oppenheimer-breakdown corrections

“…In the first place, it has been found in previous fits [24][25][26][27][28][29][30][31][32][33][34][35] that it is not possible to determine the expansion coefficients of all of Q i ðrÞ, R ð rÞ, and S i ðrÞ simultaneously. This often seems to be attributed to a shortage of data, but it is actually due to an indeterminacy in the Hamiltonian [13] that can be removed by a transformation that reduces Q Q i ðrÞ to zero.…”

“…The BOB corrections have been widely studied for the LiH molecule [15,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35] because it has two light atoms with large fractional isotopic changes in mass, the two isotopes of the Li atom can be studied at natural abundance, and there is a large amount of pure rotational data because of the existence of a dipole moment.…”

“…2. Constraining the t i n coefficients to values calculated ab initio [15,29,35] or from Stark and Zeeman data, using Eq. (35) [28,30,32].…”

Representing Potential Energy Functions by Expansions in Orthogonal Polynomials. Generalized SPF Potentials

“…Parr and White introduced and Simons, Parr, and Finlan (SPF) applied and treated in some detail a power series for W ( R ) in the variable (1 − R e / R ). This expansion has since seen many applications. − In the present paper, we refine, systematize, and extend the SPF approach.…”