holsch_2019

N. Hölsch, M. Beyer, E. J. Salumbides, K. S. E. Eikema, W. Ubachs, C. Jungen and F. Merkt, “Benchmarking Theory with an Improved Measurement of the Ionization and Dissociation Energies of H2”, Phys. Rev. Lett. 122, 103002 (2019)

Source record · Catalogue · Review register

DOI: 10.1103/PhysRevLett.122.103002

Source kind: measurement

Recorded technique: The ionisation energy of ortho-H2 as a sum of three intervals (Table II): (1) X (v = 0, N = 1) -> EF (0, 1), by Ramsey-comb spectroscopy (Altmann et al., their Ref. 36); (2) EF (0, 1) -> 54p1_1 (v+ = 0, S = 0) Rydberg state, measured here with a single-mode cw UV laser (frequency-doubled Ti:Sa, comb-calibrated) in a skimmed, pulsed, cryogenically cooled (80 K valve) H2 beam, EF (0, 1) prepared by VUV excitation of B’ (0, 0) and spontaneous emission, Rydberg states detected by pulsed-field ionisation, first-order Doppler shift cancelled with a retroreflected beam; (3) the binding energy of 54p1_1 from millimetre-wave spectroscopy and multichannel quantum-defect theory (Ref. 35) (pp. 1-4).

Materials in structured entries: H2

Dataset quantities: ionization_energy

Contents: 1 dataset; 0 formulas.

Curation notes

PRL pages 103002-1 to -5 (PDF pages 1-6; pages cited are PDF pages). Identity checked on the first page. H2 only.

EXTRACTED: Table II (p. 4, tbl_7f08590ec4cc, image checked) row (4), E_I^ortho(H2) = 124 357.238 003(11) cm^-1 ‘(340 kHz)’, also in the text (p. 4). It is the interval X+ (v+ = 0, N+ = 1, hyperfine centre) - X (v = 0, N = 1): the ionisation energy of ORTHO-H2, from the neutral’s lowest ortho level (N = 1) to the cation’s N+ = 1 level. It is not the conventional ionisation energy from X (v = 0, N = 0) to X+ (v+ = 0, N+ = 0), which would need the X (0,1) - X (0,0) interval; the paper does not give that interval, so no para value is derived here. The relative accuracy is 9.1e-11 (p. 5). In eV (not printed; hc = 1.239841984e-4 eV cm): 15.4183325 eV.

UNCERTAINTY: the final uncertainty of interval (2) combines the statistical (1 sigma, ‘standard deviation of the mean’, Fig. 3) and systematic contributions of Table I in quadrature (p. 4: ‘Adding the corrections listed in Table I and combining all uncertainties in quadrature yields the value of 755 776 720.21(30) MHz’); the total for E_I^ortho is 340 kHz = 1.1e-5 cm^-1. The confidence level of the total is not named.

ERROR BUDGET (Table I, p. 4, tbl_f99eeb49535c; the 54p1_1 <- EF (0, 1) frequency): measured 755 776 720.84(18) MHz; uncertainties dc Stark 10 kHz, ac Stark 5 kHz, Zeeman 10 kHz, pressure 1 kHz, first-order Doppler 200 kHz, second-order Doppler 1 kHz (correction +8 kHz), line-shape model 100 kHz, hfs of EF (0, 1) 100 kHz (estimated by MQDT), photon-recoil shift correction -634 kHz; systematic total 250 kHz; final 755 776 720.21(18)stat(25)sys MHz = 25 209.997 785(10) cm^-1. The main uncertainties are the unresolved hfs of EF (0, 1), the residual Doppler shift and the line-shape model (p. 5).

TABLE II, the other intervals (cm^-1, notes only): (1) EF (0, 1) - X (0, 1) 99 109.731 204 9(24) (73 kHz) [36]; (2) 54p1_1 (v+ = 0, S = 0, centre) - EF (0, 1) 25 209.997 785(10) (300 kHz); (3) X+ (0, 1, centre) - 54p1_1 37.509 013(5) (150 kHz) [35]; (5) D0^(N+=0)(H2+) 21 379.350 249 6(6) (18 kHz) [32]; (6) X+ (0, 1, centre) - X+ (0, 0) 58.233 675 097 4(8) (25 Hz) [33]; (7) D0^(N+=1)(H2+) = (5) - (6) 21 321.116 574 5(6); (8) E_I(H) 109 678.771 743 07(10) (3 kHz) [31]; (9) D0^(N=1)(H2) = (4) + (7) - (8) = 35 999.582 834(11) cm^-1 (340 kHz). Footnote a: the first two columns of Table II of Ref. 36 contain errors; the 54p1_1 binding energy and the para dissociation energy there should read 37.509 013(10) and 36 118.069 62(37) cm^-1.

DISSOCIATION ENERGY (notes; no quantity): D0^(N=1)(H2) = 35 999.582 834(11) cm^-1 (abstract, p. 4), against the theory of Puchalski et al. (PRL 122, 103003 (2019)) 35 999.582 820(26) cm^-1 and the earlier measurement via GK (0, 1) 35 999.582 894(25) cm^-1 [20], from which it differs by about 2 sigma (p. 5). The 2009 values of D0^(N=0)(H2): experiment 36 118.0696(4) (their Ref. 19, liu_2009: 36 118.069 62(37)), theory 36 118.0695(10) cm^-1 (p. 1). This paper’s accuracy is ‘30-fold improved’ over liu_2009’s (p. 2).

Recorded bibliographic identity status: VALIDATED. This concerns identification of the source; it does not establish the scientific correctness of its contents.

Datasets

holsch_2019/ie_ortho_H2

{
  "id": "ie_ortho_H2",
  "material": "H2",
  "file": "H2/holsch_2019__ie_ortho_H2.csv",
  "table": "tbl_7f08590ec4cc",
  "quantity": "ionization_energy",
  "unit": "cm-1",
  "abscissa": "label",
  "use": "primary",
  "parameters": {
    "kind": "adiabatic",
    "final_state": "X+ 2Sigma_g+ (v+ = 0, N+ = 1), centre of the hyperfine structure",
    "initial_state": "X 1Sigma_g+ (v = 0, N = 1), ortho-H2"
  },
  "uncertainty": {
    "column": true,
    "level": "not stated"
  }
}

Table II row (4), p. 4: E_I^ortho(H2) = (1) + (2) + (3) = 124 357.238 003(11) cm^-1 (340 kHz): X+ (v+ = 0, N+ = 1, hyperfine centre) - X (v = 0, N = 1). The ORTHO ionisation energy, from N = 1 to N+ = 1: 60.253 cm^-1 below the N = 0 -> N+ = 0 value 124 417.491 13(37) cm^-1 of Liu et al. 2009 (liu_2009/ie_para_H2; not in this paper), and 3.3e-5 cm^-1 above liu_2009’s own ortho value 124 357.237 97(36) (liu_2009/ie_ortho_H2). Confidence level not named (quadrature sum of 1 sigma statistical and estimated systematic contributions).

Formulas

No formulas are recorded.

Corrections

No dataset errata are recorded in this source record.

Formula corrections, where recorded, appear with their formulas above. Curation notes may also discuss corrections or unresolved interpretation. Consult the review register for the checks and decisions.