Electronic Structures of Water and Ice

The accurate calculation of the band gap of liquid water by means of GW corrections applied to plane-wave density functional theory molecular dynamics simulations

“…The direct energy gap at G is 5.58 eV, just slightly larger than the indirect gap. The calculated energy gap is smaller than the experimental value of 8.75 eV, 17 which is not surprising since DFT functionals are known to underestimate the energy gaps of insulators and semiconductors. 52,72 We return to Fig.…”

“…39,40 The eigenvalues of the isolated H 2 O molecule originate from the interactions between O 2s, O 2p, and H 1s states. [15][16][17][18][19]33,73 There are early assignments for the four occupied eigenstates, 2a 1 (O 2s with some H 1s character), 1b 2 and 3a 1 (O 2p hybridized with H 1s), 1b 1 (non-bonding O 2p), and the lowest unoccupied 4a 1 (O 2s 2p and H 1s) and 2b 2 (O 2p and H 1s) states. 2a 1 , 1b 2 and 3a 1 belong to bonding states while 4a 1 and 2b 2 have anti-bonding characters.…”

The ultraviolet reflectance of Enceladus: Implications for surface composition

“…The Warren and Brandt (2008) compilation uses a different data set in the 390-600 nm range than the Warren (1984) compilation, and leaves a gap in the 200-390 nm range. The data in the 45-161 nm region is for 80 K crystalline water ice (Seki et al, 1981), while the data in the 180-185 nm region (Minton, 1971) is for ice at 223-263 K. As pointed out by Warren (1984), Shibaguchi et al (1977) measured only small variations in optical density with temperature (83-160 K) in the 120-150 nm region; any temperature dependence in the optical constants of water ice at k > 150 nm is unknown. The Warren and Brandt (2008) data focus mainly on temperatures applicable at Earth; thus, we are not aware of a consistent data set for Enceladus-like (e.g., 80 K) temperatures throughout the UV wavelength range (though at least one group is working on such measurements (M. Gudipati, personal communication)).…”

Direct observation of the absorption bands of the first electronic transition in liquid H2O and D2O by attenuated total reflectance far-UV spectroscopy

“…3 It is also noteworthy that the X 1 A 1 → Ã 1 B 1 absorption band shows a blueshift with the condensation of water. The band maximum of water is observed at 7.4, 8.3, and 8.6 eV for the vapor, 4,5 liquid, [6][7][8] and solid states, 9,10 respectively. This fact can be generally explained in terms of the change in the hydrogen bonding in water that accompanies the perturbation of the lone-pair valence band edge.…”