Inhomogeneous Electron Gas
Physical Review, 1964 · paper · Physics
Proves that the ground-state energy of an interacting electron gas in an external potential is given by minimizing a universal functional of the electron density. Examines this functional for nearly uniform and slowly varying densities, and extends Thomas-Fermi methods.
Checked: PDF from courses.physics.ucsd.edu, fetched 5 Oct 2026. Page numbers are those of that PDF.
8 findings
Substance Eq. (42) prints "k_T ≡ (4k_F)^{1/2}". The paper's own Eqs. (41), (43), (50), (51) and (78) give k_T² = 4k_F/π, so a factor 1/π appears to be missing.
- p. 4 Eq. (42)
kT≡(4kF)1/2
- p. 4 Eq. (42)
kT ≡ (4kF)^{1/2}
- p. 4 Eq. (42)
k_T ≡ (4k_F)^{1/2}
Only the authors can say what is right here.
Judge's note: My own working, from the page images (pp. 4–6). Eq. (50) gives g0 = (3/10)(3π²)^{2/3} n^{5/3}. With Eq. (51), g0'' = (1/3)(3π²)^{2/3} n^{-1/3} = k_F²/(3n) = π²/k_F, so g0''/4π = π/(4k_F). From Eq. (43), S(q)→1 as q→0, because ln|(q+2k_F)/(q−2k_F)| ≈ q/k_F. Eq. (41) then gives α ≈ 1 − q²/k_T², so c2 = −1/k_T². Eq. (78), g0''/4π = −c2, therefore requires 1/k_T² = π/(4k_F), i.e. k_T² = 4k_F/π, not the printed 4k_F. Eq. (58) carries the 2^{7/2}/3π factor, which is consistent with ħ = m = e = 1, so a unit convention does not absorb the π. The image shows no π in Eq. (42).
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Substance Eq. (88) is introduced as the random-phase expression "Eq. (41), which gives", but prints "α(q) = (2π/k_T²)[1 + (q²/k_T²)S(q)]^{-1}". The prefactor 2π/k_T² is absent from Eq. (41), α(q) = [1 + (q²/k_T²)S(q)]^{-1}.
- p. 7 Eq. (88)
α(q)=2π/kT² [1+ q²/kT² S(q)]^-1
- p. 4 Eq. (41)
α(q)=[1+(q²/kT²)S(q)]^-1
- p. 7 Eq. (88)
α(q) = 2π/k_T² [1 + q²/k_T² S(q)]^-1
- p. 4 Eq. (41)
α(q)=[1+(q²/k_T²)S(q)]^-1
Judge's note: Compared Eq. (41) on p. 4 with Eq. (88) on p. 7. At q→0, where S→1, Eq. (41) gives α→1, consistent with Eq. (38), α = 1 + c2q² + …, and with Fig. 1 (α(0) = 1.0). Eq. (88) gives 2π/k_T² instead. The text explicitly says Eq. (88) is what Eq. (41) gives, so this is one quantity printed in two inconsistent forms.
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Reference or label The coefficients in Eqs. (85) and (87), "2.21/rs² − 0.916/rs …" and "0.88/(rs+7.8)", are in Rydbergs. Footnote 10 declares atomic units, and Eq. (50) implies 1.105/rs² Hartree. No unit is stated.
- p. 7 Eq. (85)
2.21
- p. 7 Eq. (87)
0.88
- p. 2 Footnote 10
Atomic units are used.
Only the authors can say what is right here.
Judge's note: Eq. (50) gives a kinetic energy per electron of (3/10)kF², with kF=1.919/rs, which is 1.105/rs² in the declared units. The printed 2.21 is twice this value, i.e. the Rydberg value. The unit label is missing or inconsistent.
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Reference or label Page 4 refers to "the gradient expansion (49) of G[n]". The gradient expansion of G[n] is Eq. (48); Eq. (49) is the asymptotic Friedel form of K(r).
- p. 4 Text following Eq. (49), right column
the gradient expansion (49) of G[n]
- p. 4 Sec. II.3, paragraph after Eq. (49)
gradient expansion (49) of G[n]
Judge's note: On the page-4 image, Eq. (48) is G[n] = G[n0] + 2π[−c2∫ñ² + (c2²−c4)∫|∇ñ|² + …], followed by 'i.e., a gradient expansion'. Eq. (49) is r→∞: K(r) ~ const cos(2k_F r+δ)/r³. The sentence cites (49) for the gradient expansion, which is a wrong equation pointer.
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Reference or label Page 4 says "The power-series expansion of K(q), (43), leads to". Eq. (43) defines S(q); the power-series expansion of K(q) is Eq. (44).
- p. 4 Text before Eq. (47)
The power-series expansion of K(q), (43), leads to
Judge's note: Checked on the page-4 image. Eq. (43) defines S(q), and Eq. (44) is q→0: K(q) = 2π[−c2 + (c2²−c4)q² + …]. Later in the same column the paper itself writes 'power-series expansion (44) of K(q)'.
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Reference or label Footnote 15 reads "E. P. Wigner, Phys. Rev. 40, 1002 (1934)." The volume appears to be wrong; the 1934 paper is believed to be in volume 46.
- p. 7 Footnote 15
E. P. Wigner, Phys. Rev. 40, 1002 (1934).
- p. 7 footnote 15
E. P. Wigner, Phys. Rev. 40, 1002 (1934)
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: Wigner's 1934 paper is Phys. Rev. 46, 1002, and Phys. Rev. volume 40 is from 1932. The page-7 image confirms that footnote 15 prints volume 40 with year 1934 and page 1002.
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Wording In Eq. (34) the last term reads "(λ³/Ω) Σ K(q)|b1(q)|²". The quadratic K term of Eq. (24), with ñ of order λ from Eq. (28), is of order λ², the same as the other terms used to obtain Eq. (35).
- p. 4 Eq. (34)
λ³/Ω Σ K(q)|b1(q)|²
Only the authors can say what is right here.
Judge's note: On the page-4 image the last term of Eq. (34) appears with λ³ over Ω, while the other terms show λ². My working: substituting ñ = (λ/Ω)Σ b1 e^{-iq·r} (Eq. 28) into ∫K(r−r')ñ(r)ñ(r')drdr' with Eq. (25) gives (λ²/Ω)ΣK(q)|b1(q)|². Equating the λ² terms of Eqs. (33) and (34) then gives Eq. (35), K = (2π/q²)(1/α − 1). The exponent should be 2, and Eq. (35) is unaffected. The text layer for this term is garbled ('+—2 K(q)'), so the reading rests on the image.
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Wording Eq. (47) prints "K(r) = 2π[−c2 + (c2²−c4)∇² + ···]δ(r)". Under Eq. (25), K(r) = (1/Ω)ΣK(q)e^{-iq·r}, a q² term in Eq. (44) corresponds to −∇²δ(r). The sign of the ∇² term is therefore inconsistent with Eqs. (44) and (48).
- p. 4 Eq. (47)
K(r)=2π[−c2+(c2²−c4)∇²+···]δ(r)
Only the authors can say what is right here.
Judge's note: My working: ∇²e^{-iq·r} = −q²e^{-iq·r}, so (1/Ω)Σ q² e^{-iq·r} = −∇²δ(r). Eq. (44) therefore gives K(r) = 2π[−c2 − (c2²−c4)∇² + …]δ(r). Integrating by parts, ∫ñ(−∇²ñ) = ∫|∇ñ|², which reproduces the printed +(c2²−c4)∫|∇ñ|² in Eq. (48). With the printed +∇² in Eq. (47), Eq. (48) would carry a minus sign. Eq. (48) is consistent with Eq. (44); only the intermediate Eq. (47) disagrees.
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5 minor (typos and the like; most checked by the judge only)
Reference or label Footnote 13 reads "J. S. Langer and S. H. Vosko, Phys. Chem. Solids 12, 196 (1960)"; the journal abbreviation lacks the leading "J.".
- p. 4 Footnote 13
Phys. Chem. Solids 12, 196
Only the authors can say what is right here.
Judge's note: Rests on outside knowledge: that the journal is J. Phys. Chem. Solids. The crop confirms that the printed text has no "J." before Phys.
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Reference or label The text reads "this has the opposite sign from the random-phase approximation expression (88)". The sign comparison is between the g2^(2) of Eq. (92) and the RPA g2^(2) of Eq. (89); Eq. (88) is the RPA α(q).
- p. 7 Sec. III.5b, after Eq. (92)
from the random-phase approximation expression (88)
- p. 7 Sec. III.5.b, closing paragraph
opposite sign from the random-phase approximation expression (88)
Judge's note: Eq. (88) is the RPA input from which (89) follows, so the reference may be loose rather than wrong. Read literally, the pointer should be (89). The arithmetic entry checks that (92) is negative at rs=3.
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Wording The abstract says F "can be expressed entirely in terms of the correlation energy and linear and higher order electronic polarizabilities". The introduction instead says "exact ground-state energy", and Sec. III.5a uses the full kinetic+exchange+correlation energy density g0(n).
- p. 1 Abstract
expressed entirely in terms of the cor-relation energy and linear and higher order electronic polarizabilities
- p. 7 Sec. III.5a
This is the sum of the kinetic+exchange+correlation energy density
Judge's note: The abstract wording is narrower than the quantity actually used in the introduction and in Sec. III.5a. It may be loose shorthand, so this is only a wording point.
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Typo The page-1 running header misspells the month: "9 NOVEMEBR 1964" should read "9 NOVEMBER 1964".
- p. 1 Journal header, first page
9 NOVEMEBR 1964
- p. 1
9 NOVEMEBR
Judge's note: The crop of the page-1 header shows 'NOVEMEBR' printed, so this is not an OCR artefact.
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Typo The x-axes of Figs. 1 and 2 are labelled "q/q_F", a symbol never defined. The text uses k_F for the Fermi wave vector throughout.
- p. 4 Fig. 1 x-axis
q/q_F
- p. 5 Fig. 2 x-axis
q/q_F
Judge's note: The images of pp. 4–5 show 'q/q_F →' under both figures. The text uses k_F (Eqs. 42–45, 49, 51). The dashed line at 2 corresponds to q = 2k_F, so the intended quantity is clear. This is a notational inconsistency only.
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