Indirect Spin–Spin Coupling Constants in the Hydrogen Isotopologues

Abstract

The results of experimental and theoretical studies of indirect spin-spin coupling constants for hydrogen deuteride (HD), hydrogen tritide (HT), and deuterium tritide (DT) are described. The reduced coupling constants obtained from the gas-phase NMR (nuclear magnetic resonance) experiment conducted at 300 K are 2.338(1), 2.334(3), and 2.316(1) × 10(20) T(2) J(-1), while the ab initio values computed at the full configuration interaction level of theory equal 2.349(3), 2.343(3), and 2.322(3) × 10(20) T(2) J(-1) for HD, HT, and DT, respectively. The agreement of the experimental and theoretical results is improved when proper treatment of the influence of nuclear relaxation on the NMR spectrum is applied. However, there is a minor discrepancy between experiment and theory, exceeding the estimated error bars; potential sources of this discrepancy are discussed.

Nuclear Spin-Spin Coupling in HD, HT, and DT

“…In the HD molecule, the J-coupling (≈ 43 Hz) was first observed by Carr and Purcell [4]. The most accurate measurements, reported by Neronov et al [5,6] and recently by Garbacz et al [7,8], reach the accuracy of 0.01 Hz. Due to its extreme smallness, the J-coupling is potentially sensitive to the physics beyond the Standard Model (BSM).…”

“…From the other side, the finite nuclear mass effects can be inferred from experimental values for different isotopes [8] as follows. Let us subtract from the experimental values J exp (300K) the theoretical predictions J(300K) and rescale the remainder by magnetic moments of nuclei to that of HD.…”

Computational1H and13C NMR in structural and stereochemical studies

“…The 1 H (a) and 3 H (b) NMR spectra of the mixture of hydrogen isotopologs for different densities of the solvent gas, CO 2 , black points, and the best fit to these spectra, blue curves. Frequencies are referenced to ν H 0 = 500,609,356 Hz (a) and ν T 0 = 533,969,914 Hz (b) at B 0 = 11.75 T and T = 300 K. Reproduced from Garbacz, et al [ 86 ] with the permission of the American Chemical Society…”

“…The 1 H (a) and 3 H (b) NMR spectra of the mixture of hydrogen isotopologs for different densities of the solvent gas, CO 2 , black points, and the best fit to these spectra, blue curves. Frequencies are referenced to ν H 0 = 500,609,356 Hz (a) and ν T 0 = 533,969,914 Hz (b) at B 0 = 11.75 T and T = 300 K. Reproduced from Garbacz, et al [86] with the permission of the American Chemical Society huge hextuply-split Jensen's aug-pcJ-5 basis set augmented with tight and diffuse functions. Experimental couplings were obtained from the gas-phase data for different densities of the solvent gas extrapolated to a zero density, as illustrated in Figure 2.…”

A method for measurement of spin-spin couplings with sub-mHz precision using zero- to ultralow-field nuclear magnetic resonance

“…However, while the authors of Ref. [12] also measure slight discrepancies between experiment and theory for the couplings in hydrogen deuteride (HD), hydrogen tritide (HT), and deuterium tritide (DT), they suggest that the effect may be associated with the absence of nonadiabatic corrections in the theory. Along with improvements to calculations, additional precise J-coupling measurements will be valuable to these efforts.…”