Hylleraas hydride binding energy: diatomic electron affinities

Abstract

Theoretical adiabatic electron affinities are often considered inaccurate because they are referenced to only a single value. Ground state electron affinities for all the main group elements and homonuclear diatomics were identified recently using the normalized binding energy of the hydrogen atom: [0.75420375(3)/2 = 0.37710187(1) eV]. Here we revisit experimental values and extend the identifications to diatomics in the G2-1 set. We assign new ground state electron affinities: (eV) Cl2, 3.2(2); Br2, 2.87(14); CH, 2.1(2); H2, 0.6 ; NH, 1.1, SiH, 1.90. Anion Morse potentials are calculated for H2 and N2 from positive electron affinities and for hyperfine superoxide states for the first time.

Mass spectrometric determination of Morse parameters for the fifty-four superoxide states dissociating to the lowest limit

“…In Fig. the non‐linear least‐squares fits to the APIMS‐2010 and APIECD‐2010 data; the ECD‐2003, 1972, and 1971 data; the 1981 microwave swarm data; the 1979 mass spectrometry/flame data; the 1966 swarm data; and the 1944 and 1966 magnetron (MGN‐1944 and MGN‐1962, respectively) data are used to determine the E 1 in Table . The APIMS‐2010 and APIECD‐2010 data provided both ECD and mass spectrometry data .…”

“…Experimental and theoretical AE a (Z, Z 2 ) values were evaluated and assigned to predicted states from the differences in the N Hyl : dN Hyl (Z, Z 2 ) = (gs‐AE a (Z 2 ) – AE a (Z))/Hyl. The dN Hyl values for O 2 , S 2 and F 2 are –1 . The gs‐AE a (O 2 ) = –0.377 + 1.46 = 1.08 eV is generalized to AE a (O 2 ) = 0.377 dN Hyl + 1.46 eV.…”

“…Recently, Chen, Chang, Rosenthal, Chen and others postulated that the ground state electron affinity of the hydrogen atom per electron, the Hylleraas: Hyl = gs‐E a (H)/2 = 0.7542/2 = 0.3771 eV/electron, is the fundamental measure of electron correlation and assigned positive values to all atoms, Z, from N Hyl = AE a (Z)/Hyl. Experimental and theoretical AE a (Z, Z 2 ) values were evaluated and assigned to predicted states from the differences in the N Hyl : dN Hyl (Z, Z 2 ) = (gs‐AE a (Z 2 ) – AE a (Z))/Hyl.…”

“…In 1987, Herschbach recalled his 1960s classification of diatomic anions based on the signs of D e [Z 2 – ], vertical electron affinity, VE a , and the energy for dissociative electron attachment, E dea . The term D e [Z 2 – ] was replaced by r e to define 2 3 = 8 Herschbach Ionic Morse Person Electron Curves (HIMPEC) . The neutral and anion curves are: …”

“…and r e , and the frequency, ω, from the photoelectron spectra in Fig. and alkali metal superoxide data . The 27 antibonding states are defined by D e , and r e and ω from fits to O – distributions.…”