Victor Kaufman and John F. Ward, "Measurement and Calculation of Cu II, Ge II, Si II, and C I Vacuum-Ultraviolet Lines," J. Opt. Soc. Am. 56, 1591-1597 (1966)
The discharge in a water-cooled copper hollow cathode containing germanium and silicon was photographed with the NBS 10.7-m Eagle vacuum spectrograph to investigate a portion of the vacuum-ultraviolet spectrum of singly ionized copper in first, second, and third orders. The suitability for use as standards of thirty-two of the thirty-three Cu ii lines of the 4p–6s transitions for which Ritz calculations have been made was investigated. One hundred and eight other lines of Cu ii in the interval 861–1623 Å were observed and measured in the second and/or third orders, with estimated wavelength uncertainties of 0.0006 Å. These include two previously unobserved lines of the 4p–6s transitions, five members of the calculable 4s–5p transitions, and the three ground-state transitions (a1S0–4p1P1, 3P1, 3D1). The improved data for these three lines improve the accuracy of calculated shorter-wavelength lines.
Some vacuum-ultraviolet multiplets of C i, Si ii, and Ge ii in the wavelength range 1492–1602 Å, were also measured in second order. They lead to an extension, modification, or confirmation of previously calculated wavelengths of these spectra. A precise measurement of the Lyman Beta line of hydrogen in third order provides added confirmation of the presence of the Lamb shift of the 1 2S state of hydrogen.
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Calculated from the Cu n term values as given by Edlén in Trans. IAU XIIA, 143 (1965).
Third order of, this line is 0.004 Å from the second order of the Cu ii line at 1541.7542 Å and would not be useful as a standard in that order.
The low intensity of this line, which was observed in first order only, reduces its usefulness as a standard.
The very low intensity of this line, which was not observed by us, precludes its use as a standard except when the remainder of the Cu ii spectrum is overexposed.
This line was used as a standard throughout the course of this work, e.g. as an end point for the correction curve. No new value is therefore offered for this line.
This is a newly observed and classified line of the 4p–6s group of transitions.
The low intensity of this line and its proximity to 1485.67 Å reduces its usefulness as a standard. The estimated uncertainty of the measured value is ±0.002 Å.
This may be a blend. The double classification indicates that two lines with a separation of about 0.006 Å are to be expected. No indication of this was seen.
Although Shenstone9 has a triple classification for this line, it appears that only the 4p–6s classification is correct.
No reason can be given for the poor agreement of the measured and calculated values of this line. Note, however, from Table III, that this is the strongest line of Cu ii in this region.
The low intensity of this line, which was observed in first order only, reduces its usefulness as a standard. The estimated uncertainty of the measured value is ±0.002 Å.
This line was observed in first order only and was measured with respect to calculated wavelengths of Ge i and Si i.
This line, given by Shenstone with an intensity equivalent to that of many of the other lines present, was not observed. No explanation can be given at this time.
Table II
Transitions to the ground state, 3d10 1S0, from the 3d9 4p J = 1 levels of Cu+.
Upper level
3P1°
3D1°
1P1°
meas. wavelength (Å)
1472.3946
1367.9508
1358.7736
meas. wavenumber (cm−1)
67916.576
73102.044
73595.778
old level value (cm−1)
67916.383
73101.869
73595.642
difference (cm−1)
0.193
0.175
0.136
average difference to be added to each level = 0.168 cm−1
new level value (cm−1)
67916.551
73102.037
73595.810
calc. wavelength (Å)
1472.3951
1367.9510
1358.7730
Table III
Newly measured and intercompared auxiliary standards of Cu ii in the vacuum ultraviolet.
The intensities are visual estimates of photographic plate blackening.
This wavelength value results from the calculation of the wavenumber of the transition from a J = 1 level of the 3d9 5p configuration to the 3d10S0 ground state.
This wavelength is a calculated value and is taken from Ref. 1 or is calculated from the term values given by Edlén in Trans. IAU 12A, 143 (1965). The relative intensity and other data pertinent to this line refer to the actual observations.
This wavelength value results from the calculation of the wavenumber of the transition from a J = 1 level of the 3d94p configuration to the 3d101S0 ground state (see Table II).
The proximity of this line to N i 1492.8195 Å may lower its usefulness as a standard.
Shenstone gives more than one classification for this line. Although one of the classifications permits a calculation of the wavelength, this observed value is to be preferred.
The large difference between the calculated and observed value of this line leads us to insert the observed value. Possibly this line should not be considered as a standard until this discrepancy is accounted for.
This newly observed and classified line (4s2 1D2–t3P2) may interfere in second order with the third order image of the line at 1027.8 Å.
Table IV
Newly measured auxiliary standards in the vacuum ultraviolet and other pertinent lines.
All wavelengths are those in vacuum. The estimated wavelength uncertainty of those lines observed in first order is ±0.0010 Å. Those lines measured in higher orders have an estimated uncertainty of ±0.0006 Å.
Intensities given for Ge ii and Si ii are those of Shenstone in. Refs. 10 and 11, respectively.
Possible interference with this line by 1576-Å Si i increases its estimated uncertainty to ±0.0010 Å.
This line was reported by Kaufman, Radziemski, and Andrew and is included here for completeness.
Table V
Partial energy level array of the singly ionized germanium atom.
The wavelength uncertainty for this line is, at most, ±0.0010 Å. Wavelengths listed with no superscript have uncertainties estimated to be ±0.0005 Å or less.
Table VIII
Partial energy-level array of the neutral carbon atom.
The odd-level values are those of Johansson14 increased by 0.01 cm−1. σcalc − σobs. σobs.
The wavenumber values for the 2s 2p2 3P–2s 2p3 3P° multiplet are from Herzberg.15
This line was not observed.
Tables (8)
Table I
Comparison of calculated and observed wavelengths of Cu ii.
Calculated from the Cu n term values as given by Edlén in Trans. IAU XIIA, 143 (1965).
Third order of, this line is 0.004 Å from the second order of the Cu ii line at 1541.7542 Å and would not be useful as a standard in that order.
The low intensity of this line, which was observed in first order only, reduces its usefulness as a standard.
The very low intensity of this line, which was not observed by us, precludes its use as a standard except when the remainder of the Cu ii spectrum is overexposed.
This line was used as a standard throughout the course of this work, e.g. as an end point for the correction curve. No new value is therefore offered for this line.
This is a newly observed and classified line of the 4p–6s group of transitions.
The low intensity of this line and its proximity to 1485.67 Å reduces its usefulness as a standard. The estimated uncertainty of the measured value is ±0.002 Å.
This may be a blend. The double classification indicates that two lines with a separation of about 0.006 Å are to be expected. No indication of this was seen.
Although Shenstone9 has a triple classification for this line, it appears that only the 4p–6s classification is correct.
No reason can be given for the poor agreement of the measured and calculated values of this line. Note, however, from Table III, that this is the strongest line of Cu ii in this region.
The low intensity of this line, which was observed in first order only, reduces its usefulness as a standard. The estimated uncertainty of the measured value is ±0.002 Å.
This line was observed in first order only and was measured with respect to calculated wavelengths of Ge i and Si i.
This line, given by Shenstone with an intensity equivalent to that of many of the other lines present, was not observed. No explanation can be given at this time.
Table II
Transitions to the ground state, 3d10 1S0, from the 3d9 4p J = 1 levels of Cu+.
Upper level
3P1°
3D1°
1P1°
meas. wavelength (Å)
1472.3946
1367.9508
1358.7736
meas. wavenumber (cm−1)
67916.576
73102.044
73595.778
old level value (cm−1)
67916.383
73101.869
73595.642
difference (cm−1)
0.193
0.175
0.136
average difference to be added to each level = 0.168 cm−1
new level value (cm−1)
67916.551
73102.037
73595.810
calc. wavelength (Å)
1472.3951
1367.9510
1358.7730
Table III
Newly measured and intercompared auxiliary standards of Cu ii in the vacuum ultraviolet.
The intensities are visual estimates of photographic plate blackening.
This wavelength value results from the calculation of the wavenumber of the transition from a J = 1 level of the 3d9 5p configuration to the 3d10S0 ground state.
This wavelength is a calculated value and is taken from Ref. 1 or is calculated from the term values given by Edlén in Trans. IAU 12A, 143 (1965). The relative intensity and other data pertinent to this line refer to the actual observations.
This wavelength value results from the calculation of the wavenumber of the transition from a J = 1 level of the 3d94p configuration to the 3d101S0 ground state (see Table II).
The proximity of this line to N i 1492.8195 Å may lower its usefulness as a standard.
Shenstone gives more than one classification for this line. Although one of the classifications permits a calculation of the wavelength, this observed value is to be preferred.
The large difference between the calculated and observed value of this line leads us to insert the observed value. Possibly this line should not be considered as a standard until this discrepancy is accounted for.
This newly observed and classified line (4s2 1D2–t3P2) may interfere in second order with the third order image of the line at 1027.8 Å.
Table IV
Newly measured auxiliary standards in the vacuum ultraviolet and other pertinent lines.
All wavelengths are those in vacuum. The estimated wavelength uncertainty of those lines observed in first order is ±0.0010 Å. Those lines measured in higher orders have an estimated uncertainty of ±0.0006 Å.
Intensities given for Ge ii and Si ii are those of Shenstone in. Refs. 10 and 11, respectively.
Possible interference with this line by 1576-Å Si i increases its estimated uncertainty to ±0.0010 Å.
This line was reported by Kaufman, Radziemski, and Andrew and is included here for completeness.
Table V
Partial energy level array of the singly ionized germanium atom.
The wavelength uncertainty for this line is, at most, ±0.0010 Å. Wavelengths listed with no superscript have uncertainties estimated to be ±0.0005 Å or less.
Table VIII
Partial energy-level array of the neutral carbon atom.
The odd-level values are those of Johansson14 increased by 0.01 cm−1. σcalc − σobs. σobs.
The wavenumber values for the 2s 2p2 3P–2s 2p3 3P° multiplet are from Herzberg.15
This line was not observed.
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