S 549

WAVE-LENGTH MEASUREMENTS IN THE ARCSPECTRUM OF SCANDIUM

By William F. Meggers

ABSTRACT

The wave lengths corresponding to approximately 700 lines photographed inthe 220-volt arc spectrum of scandium were measured relative to secondarystandards in the iron spectrum. These values extend from 2540.87 in theultra-violet to 8644.48 A in the infra-red; the majority are lines characteristicof neutral scandium atoms, a considerable number of lines originate with singlyionized, and a few with doubly ionized, atoms. Bands characteristic of scandiumoxide molecules appear very prominently in the longer wave portions of thespectrum.

CONTENTSPage

I. Introduction 61

II. Experimental 62

III. Results 63

IV. Bibliography 71

I. INTRODUCTION

Since 1914 the spectroscopy section of this bureau has followed

a program of standard wave-length determination and spectroscopic

analysis, the main object of which has been to describe what may becalled the standard spectra of each of the pure chemical elements.

The descriptions which have been available heretofore have oftenbeen of a qualitative character and sometimes lamentably incom-

plete, notwithstanding the great importance of more precise data forcertain optical measurements, for the spectrochemical identification

of the elements, and for the study of atomic structure and the

mechanism of radiation. Since other investigators have also beenengaged in improving these descriptions of spectra, our efforts

in the past have been confined for the most part to the region oflonger waves which has been almost entirely neglected by others.The application of photographic sensitizers to these spectroscopicinvestigations has resulted in extending the descriptions of the arc

emission spectra of many of the chemical elements in the red andadjacent infra-red regions. Such data have already been published

for lithium, sodium, potassium, rubidium, caesium, copper, strontium,

calcium, barium, magnesium (1),^ iron, cobalt, nickel (2), neon (3)

1 The figures given in parentheses here and throughout the text relate to the reference numbers in thebibliography given at the end of this paper.

43166"—27 61

62 Scientific Pajpers oj the Bureau oj Standards . [Voi.m

krypton, xenon (4), titanium, vanadium, chromium, manganese,molybdenum, tungsten, uranium (5), silver, aluminum, gold, bis-muth, cadmium, mercury, lead, antimony, tin, zinc (6), yttrium,lanthanum, cerium (7), neodymium, samarium (8), gadolinium,dysprosium (9), ruthenium, rhodium, palladium, osmium, iridium,platinum (10), and zirconium (11). For the last-named element thespectra were investigated throughout the entire range of wavelengths accessible with our grating spectrographs (2200 to 9500 A),

and the same statement can now be made for scandium. The longwave portion of the arc spectrum of scandium was photographedand measured in this laboratory in 1923, at which time, since nospectra of this element had ever been measured in the new inter-national scale of wave lengths, it was decided to extend the observa-tions through the visible and ultra-violet regions. This work has beencompleted, and the purpose of the present paper is to present theresults of wave-length measurements in the arc spectrum of scandiumfrom the ultra-violet at 2300 A to the infra-red near 9000 A.

II. EXPERIMENTAL

Scandium (Sc = 45.1; Z = 21) has long been regarded by mostchemists as one of the so-called ^'rare earth" family of elements,

and it still remains one of these in the sense that it is very scarceand extremely difficult to obtain in purified form. The present obser-vations were made with 1 g of scandium ammonium oxalate carefullypurified by Auer von Welsbach and acquired as a part of a collectionof chemicals and spectrograms purchased from Prof. J. M. Eder, ofVienna, in 1920, when he discontinued his spectroscopic researches.

For the excitation of the characteristic spectra of scandium, the

material was used on electrodes of copper or of silver between whichan electric arc of 4 to 6 amperes direct current was produced with

a potential difference of 220 volts. Exposures were made with bothkinds of electrodes throughout the entire spectral range to eliminate

the possibility of overlooking Sc lines which might be masked bylines either of Cu or of Ag.As pointed out in connection with wave-length measurements in

arc spectra of certain metals of the Pd and Pt triads (12), the use ofarc electrodes of Cu or Ag for the excitation of spectra of pure salts,metal sponges, etc., is especially convenient when the arc-streamcolor of the applied material is different from that of the metalelectrodes. Silver and copper arcs both give an intense yellow-green

flame, but scandium, on account of strong emission lines and bands

in the red portion of the spectrum, imparts a very decided reddish

tinge to the flame when it is carrying an effective part of the current.When the red disappears and only yellow green remains, it is anindication that no appreciable amount of scandium is being vaporizedin the arc.

Meggers] Afc Spectrum oj Scandium 63

The wave lengths were derived from diffraction grating spectro-grams, the arc spectrum of iron being either superposed or juxtaposed

to supply the standard wave lengths from which the values forscandium lines were derived by interpolation. A blank spectrogramof the Cu or Ag electrodes was usually photographed on the sameplate to avoid the necessity of measuring and subsequently eliminating

the Cu or Ag spectra.Two diffraction gratings, each 640 cm radius of curvature, were

alternately used in making the spectrograms. They were used inparallel light in the mounting described in our earlier papers (13).For the red and infra-red regions a 6-inch grating ruled by Andersonwith 7,500 lines per inch, giving a scale of 10 A per mm, was employed,while the remainder of the spectrum was recorded with a similar

grating, ruled by Rowland, with 20,000 lines per inch, which gave adispersion of about 3.6 A per mm in the first-order spectrum.

Photographic plates procured fron Schleussner, of Frankfurt a. M.,

were used for all the exposures because they had sensitive emulsions

coated on long strips of extra-thin glass (6 by 40 cm and less than0.1 cm thick) which permitted bending them to fit the focal curve ofthe spectrograph. Three Sc exposures made by Eder on similarplates were found in the collection of spectrograms which he con-

signed to us. These extended over the interval 5500 to 6800 A; they

were measured and averaged with the results of our own spectrograms.The observations extended in the ultra-violet to 2250 A, but no

scandium lines shorter than 2540 A were photographed. Forphotographing the yellow and red portions of spectra the plates werebathed in solutions of pinaverdol and pinacyanol, and for recording

the infra-red sensitizing solutions of dicyanin were employed. Theline of greatest wave length thus recorded with exposures of onehour duration was 8644 A. Very recently an attempt was made tophotograph still longer waves of scandium with a neocyanin-bathedplate, but no new lines were found. This may, however, be attributedto excessive economy of exposure and of scandium, since the amountof material available had by that time dwindled to almost nothing.

III. RESULTS

Descriptions of scandium spectra in limited wave-length intervalshave been made by various observers. The most reliable ones upto the year 1911 are quoted by Kayser in Volume VI of his Hand-buch der Spectroscopic; they are by Lockyer and Baxandall (14)(arc spectrum from 3907.62 to 5717.54 A), by Fowler (15) (arcspectrum 3933.55 to 6558.28 A), by Exner and Haschek (16) (arcspectrum 2438.74 to 6604.88, and spark spectrum 2233.03 to 6604.90A), and by Eder and Valenta (17) (arc spectrum 5514.46 to 6835.20A). Reproductions of the spectra and additional lists of the strongerlines appeared in the Atlas Typischer Spektren, published by Eder

64 Scientific Papers of the Bureau oj Standards [voi. 2^

and Valenta, in 1911. They give three tables of wave lengths whichcontain 184 lines measured in the arc spectrum (3251.43 to 6835.30

A), 180 lines observed in the spark spectrum (3429.59 to 6835.30 A),

and 65 heads of bands in the scandium oxide spectrum (4672.85 to6700.64 A). All of the above-mentioned measurements of scandium

spectra were based on Rowland's system of standard wave lengths.More recently, lists of wave lengths from the scandium arc were

published by Crookes (18) and by Pina de Rubies (19). The firstcontains 101 lines (2420.025 to 6305.7 A) and the second 185 lines

(2232.0 to 3394.2 A). Both are of doubtful value, because themeasurements were made from relatively small-scale prism spectro-grams and the results are very sketchy and qualitative.

In the Schumann region observations by Ireton (20) describe 45 linesin the spark spectrum of scandium (507.0 to 2233.7 A). Smith (21)has supplemented these for the purpose of analyzing the structure of

the Sc III spectrum by measuring several lines (730.60 to 2012.95 A).Three other investigations, which are of inestimable value as

descriptions of scandium spectra, must be mentioned, althoughthey contribute nothing to the wave-length data. They are {a)the electric furnace spectrum of scandium as reported by King (22),(6) magnetic resolutions in the scandium spectrum by Goudsmit,van der Mark, and Zeeman (23), and (c) the absorption spectrum ofscandium as described by Gieseler and Grotrian (24). King'sobservations extend from 3015.50 to 6558.28 A, the arc intensity,

and furnace intensities at low, medium, and high temperaturesbeing given for nearly 300 lines. In the second investigation men-tioned the Zeeman effects for 30 scandium lines were determined.These identify the spectral terms which combine to produce theradiations, and are in perfect accord with the analyses of scandium

spectra as reported by Russell and Meggers (25). Twenty-fourscandium lines (3255.81 to 6413.57 A) were found by Gieseler andGrotrian to be absorbed in scandium vapor at 2000° C; these obser-vations, in connection with the Zeeman effects just mentioned, firmlyestablish the fact that the normal state of the scandium atom isdescribed by a doublet-D spectroscopic term.The results of our measurements of approximately 700 wave lengths

in the arc spectrum of scandium are presented in Table 1. Wavelengths under standard observing conditions appear in the first

column, our intensity estimates and notes in the second. King's arc

intensities and temperature classes in the third, and vacuum wavenumbers in the last. The probable errors of the wave lengthsobtained with the larger scale grating—that is, shorter than 6,000 A

—

are rarely greater than 0.01 A except for faint lines which were ob-served only once. In the red and infra-red, for which the scale of the

spectrograms was nearly three times as compressed, the errors arenaturally larger; they probably average between 0.02 and 0.03 A.

Meggers] Avc Spectrum of Scandium 65

This applies especially to heads of bands, the effective wave lengthsof which, on account of their unsymmetrical character, varied con-siderably with the strength of the exposure. In making intensityestimates we have attempted to make finer gradations than are pos-sible with the 1-10 scale which most spectroscopists use. The ratioof the weakest to the strongest lines was assumed to be 1 to 100, andlines of intermediate intensity were assigned intensities proportional

to their estimated strength on this scale, except that a few very weaklines observed only on the strongest exposure are marked "0.^^ Ourrelative intensities over restricted wave-length intervals appear to be

roughly proportional to King's values, but the ratio of the two sets

of estimates varies somewhat from one portion of the spectrum toanother, probably on account of differences in the spectrographs,

exposures, and photographic plates.

A suggested chemical symbol accompanies the intensity estimatewhen there is a possibility that a part of the line may be assignedto an impurity. The remaining symbols have the following meanings

:

e=line enhanced at the negative electrode of the arc;

n=band head;p= part of band structure;1= shaded to long wave lengths;h=hazy;d= double;

The vacuum wave numbers in the last column of Table 1 arederived from the wave lengths in the first column with the aid ofKayser's Tabelle der Schwingungszahlen. They are printed especiallyfor the benefit of those interested in the structures of the various

spectra displayed in Table 1, since the combination principle reveals

true spectral regularities only when frequencies or proportional wavenumbers are employed. Without going into details concerning the

structures of various spectra of scandium, it suffices to state that four

distinct types of spectra are present in Table 1; they are (a) the

banded spectrum characteristic of scandium oxide molecules, (6) a

line spectrum (Sc I) coming from excited neutral atoms of scandiimi,

(c) a second line spectrum (Sc II), originating with singly ionized

atoms of scandium, and (d) a third line spectrum (Sc III) arising from

doubly ionized scandium atoms. These various spectra are all

represented among the radiations from a 220-volt arc in which scan-dium vapor is present, and Table 1, which is intended to present afaithful description of the so-called arc spectrum of scandium, is thus

a composite picture of four distinct scandium spectra.

No attempt has as yet been made to interpret the band spectra ofscandium compounds, but the line spectra have been very satisfac-

torily analyzed and interpreted. The latter are dealt with by Russelland Meggers in a forthcoming Bureau of Standards Scientific Paper.

c= complex;G= observed as absorption line by

Gieseler and Grotrian;Z=Zeeman effect observed by Goud-

smit, van der Mark, and Zee-man.

66 Scientific Papers oj the Bureau of Standards

Table 1.

—

Scandium spectra

[Vol.

MA Intensity andnotes

Intensity andclass

V MA Intensity andnotes

Intensity andclass

V

2540. 87 1,6 39344. 79277. 24167. 37114. 35046.84

39001. 5938284. 7137473. 93

358. 12243.58

127.96038. 14

37014. 9636933.33

917. 38

870. 95697. 71628. 07624.68664. 30

544.12400. 16390. 49324. 38

36105. 04

35930. 40842. 02771. 49686. 58

603. 21

456. 11

423.32366. 68852. 68296.14

283. 4335234. 19

34963. 11

910.00904. 16

881. 13872. 98827. 43822. 09660.32

650. 83318. 38139. 78126. 96

34072. 41

33970. 53889. 35760. 72707. 22614. 85

550. 66538. 96446. 84154.02

33110. 32

32985. 67885.85823.33746.03709.82

664, 61

630.39615,80506, 89

32489.36

3078.4679,9680.2381.6682.57

83.2886.3087,3589.7892.43

92.5294.6395.3596.8298.60

3099.443102. 15

02.3606.6706.01

06.5407.5308.5009.3510.24

12,1113.3614.7817.2017.82

19.6722.6422.9823.9524.94

26.0227.7028.2933.1233.31

38.3638.4639.7640.7446.91

68.5470.4088.2990.4191.01

3199.383215. 68

20.7733.2261.31

55.6969.91

3273. 643311.73

12.75

13.5716.7917.0617.7020.44

20.7231,0933.5343. 28

3349.22

1 32474 3745.24 6, e 1 458.66

455 7152.38 10, e ..-.:.. 1, e56.84 6, 6- 1 441 7060.26 9, e 2, e 431 07

2563. 23 8, e 1 423. 612611.23 3, e 1 402 38

67.73 1, e 1 380 8676.00 l,e 2, d 356.4084.23 2, e ... 2 327 68

92 69 1? 2, e . 326 722699. 12 6, e 1 304 692700. 81 1, e ... 1 297 18

06. 78 2 2 281 8507.95 1 1 263 30

11.36 2 1 254 6624.16 1, e? 1 226. 3829.34 1 224 2029 60 1, e 1 189 8634.10 4, e 1 186. 34

35.61 1, e , . . . 1 180 8446. 43 1, d?,e,Ag+?.- 6,6 170.6047.16 1, e 3,6 160.6652 16 1, e _ 2 151 7768 88 0, e 1. . . . 142 66

82.34 3, e 1, d?- 123.2689 20 5, e i' „ . :: 110 36

2794. 70 1, e 1 1 095. 722801. 35 6,e 1 :::. 070.8007 91 1, e 2. d 1 064. 41

19.56 6, e 1 i 045.4122 17

^,e ..........1... 1 015. 96

26.69 10, e 3,6 Oil. 4527.81 2, e 1 32001. 6232 34 2, e, Th?

1, e

1 31991. 36

33.36 1,6 980. 3237 32 2, e, Th? 1 963. 1459.32 2,6... 5:e...:.::::::i:::::::::::::::: 957. 1163.67 2, e 8,6 1 907.8664. 15 1, e 2 906.91

66.04 4, e 2? 854.5766.71 2, e i,e?. 1..:: 853. 5770 46 1, e 10, e i 840.3770 90 2, e 1 1 830.4484.30 1 1, e 768.03

2885 09 1 1. Ag? 661.062913. 04 3, e i:..:.::.:::::: :::::::::::::::: 632. 67

28.28 1 1i

366. 7429.38 4, e, Ag+? 2, 6 1 334.9034 07 2, e, Ag+? 5,6 1 . 329. 01

42.87 1 . .. 10, 6. 247.06088.6749 92 1 2, Ag? 1

61.16 1, Gu? 3, Ir? 1 039. 6465 86 2 1 . . 1 31020. 0374.01 5 3 1 IV 30747. 99

79.70 6, e 4, G . ... 61 A 706.6380.74 6 10,G,Z

15, G15 II A20 II A.

673. 10

2988. 95 10, e+arc 638.273015. 35 8 8 11 3,6 187. 04

19.33 10 10 II .. ... 5,6 177. 74

30.74 3 3 11 0? 170.2839.94 10,6 Ill A 1? 140.9946.73 15, e 1,6 138. 6262.92 20, e 1,6 . 132. 7266.30 1 1 IV 3 107.86

60.53 3,6 1,6 105.3363.74 3 30011. 6066.11 30, e ? . . IIIIA

1 III A d?.....IIIIA

29989. 6376.38 3,6 4 902.18

3077.04 1 ................ 29849.14

Meggers] Arc Spectrum oj Scandium

Table 1.—-Scandium spectra—Continuedm

XIAIntensity and

notesIntensity and

classV XIA Intensity and

notesIntensity and

classV

8351. 20 ? IIVA2 IV ...

29831. 51823. 95

809.01756.22751.08

742. 23736.22722. 25710. 32696.30

674. 43

646. 27633.71692.83584.42

582. 41

525. 98452. 82259.82236. 97

152.99150.61134. 64099. 03066. 45

059.9429027. 8028990.00

914. 80875.21

813. 13800. 85724. 38593. 92687. 38

672. 18522.46274. 65

28093. 3428021.29

27983.41953. 52917. 69850. 03843. 51

732. 91

718. 91

705. 09663. 54634. 62

500. 24498. 66493. 51

479. 75443.69

424. 72412. 77402. 70375. 98332. 57

282.972G5. 93201. 24191.33

27178. 32

26895. 14

397.47308.21144. 74

26114.62

3833. 0836.5139.1943.0644.22

45.4546.6652.3953.5055.62

3894. 983907.49

11.8114.9423.61

33.3752.2676.3089.06

3996. 61

4014.4920.4023.2323.6930.67

31.3834.2336.8743.7946.48

47.7949.9551.8564.5456.69

67.0074.9678.5682.4086.01

86.6687.1593.1294.85

4098. 35

4100. 3216. 7026.5633.0040.29

47.4052.3564.7460.5261.87

65.2071.5571.7677.4886.45

87.6290.6697.07

4199. 604202. 19

04.5405.2112.3412.48

4216. 10

3 26081. 31

62.05 3 1 057. 9953.73 25, Z.._. 10 III 1 039. 8069.68 10, Z . 6 III 4 - 013. 5860 26 1 1 _ - 26005 73

61.26 10 _ 6 III 1 25997. 4161.94 12

1_6 III 1 989. 24

63.52 1 950. 5864.87 ? IIIIA 1 943. 1066.46 1 1 928. 84

68.94 15 8 III 1 IIVA75 II . ...

666. 8272. 14 20, Z. 12 III 40, G, Z

60, G, Z?

584 6573. 57 1? 100 II_ 556. 4078.23 2 . . trlVA 635. 9779.19 2, e 2 480. 19

79.42 3 10 G 20 II 416 3285.88 ? IIVA 1 IIVA 294. 85

8394 29 1 1 141. 923416. 68 2 2 III A 2 061.50

19 35 1 16, G, Z

5

301 25014. 16

29.20 2 3 III A3 III A3 III A5 III A1 III A.

1 III A1 III A1 III A3 III A2 III A

IIIIA

5IVE75 II

24902. 7529.48 2 50, G, Z

1

866. 1431.36 2 2 III A

100 II848. 65

35.56 3 70, G, Z3

845. 81

39.41 ? . 802. 78

40.18 2 ^ 2 III A2 III A2 IV

798.4243.99 ? 780.9048.48 ? 764.6957.45 2 . . 3 2 III A

2 III A.

25 1

722. 3262.19 1 3 705. 88

69.65 1 10, G, Z2

697. 8971.13 1 2 III A

IIVA35 1

684.7180.37 1, Ag? 1 673. 1496.25 20, G 656. 7797.05 1 2 4 III A

2 III A2 III A2 III A40 1

644.31

3498. 91 2 2 III A 2 681. 238505. 01 1, h.. 3 633. 22

35.73 10, Z ... 6 III 2 511. 5658.66 20, Z 711 30, G 488. 5167.70 20, Z 611 1 IIIIA

4 III

466. 87

72.63 60, Z 20 II 3 462. 9876.35 35, Z 811 4 8 III 460 0580.94 30, Z 711 1 424. 3789.64 20, Z 6 11 2 IIIIA 414. 06

3590. 48 20, Z 6II.._ 2.... 393. 20

3604. 80 1 2 381. 4806.62 2 1 284. 4708.42 1 1 226. 4513.84 60, Z 30 II 5 8 III 188. 7030.76 50, Z 12 II 7 . . . . 10 III 146 11

35.30 ? 1 III 2 104. 7235.51 10 12 III 075 9836.19 2 1 062. 1338.01 1 1 028 7142.79 40, Z 25II._ l,Sr? 020.90

45.31 30, Z 10 III 10 12 III 24001. 7146.90 ? 1 III A 1 23965. 1848.24 1 ? IIIIA 963. 9751.80 25, Z 7 III 1,Y? 931. 1557.60 ? trill A 1 879. 88

64.25 1 2 873. 2166. 54 3 2 III 1 855 8976.26 1 819. 4676.60 -. . 805. 68

3678. 36 2, e 1 790.43

3717. 09 1 1 777 143787. 17 1 ...-.- 2 773 353800. 02 2? 2 733. 1123.78 1 1 732. 32

8828.19 1 2 23711. 95

68 Scientific Papers of the Bureau of Standards

Table 1.

—

Scandium spectra—Continued[Vol. MS

XIA Intensity andnotes

Intensity andclass

y MA Intensity andnotes

Intensity andclass

V

4218 25 2 2 III A2 III AIIV A2 III A

23699. 86691.60679.54658. 69624.87

623.20613. 88604.46590. 36589.19

580.68644.36540.37469.85423. 01

372. 74358.21346. 92

338. 53322. 25

277.61218. 46173. 37137.75

23114. 91

22989. 83970. 77957. 79936. 51

934.25

931. 25903.56853. 66849. 80818. 20

815. 02799. 67774. 74766. 86718. 95

640.90614. 72560.17

22007. 9221997. 60

937.02856.64832. 82766. 47741. 76

740.34710. 78688. 13686. 15683. 99

425.34405. 47395. 67381. 99359. 32

278. 36239. 16228. 52217. 71208. 12

205. 87193. 87183. 50176. 86

21141.30

4729. 2332.3034.1035.0837.66

41.0243.8146.1648.9763.16

58.9163.1271.4479.3591.60

4792.844827.28

33.6639.4440.46

40.8647.6752.0852.6767.78

58.0759.1778.1680.7290.34

4893. 004906. 65

09.7522.8434.25

36.7541.3151. 2851.6864.06

73.6580.3683.4490.1191.91

4995. 01

5005. 0805.5614.1218.39

20.1421.5126.6430.28

31.02

32.7437.0344.4253.9657.13

64.3166.3868.8570.2175.81

80.0781.5683.7285.54

5086. 95

10 30 III 21139. 2019 72 2 2 2 IV A..

15 III .....125 48

21.87 1 15 117. 4526 59 2d 2 113. 0831 64 1 20 20 III 101' 63

31.94 2 2 IV A3 III A

30 - 30 III 086. 6333 61 3 40 40 HI 074 2336 30 1 ? (l)IVA

(1) IV A15 I A

(l)IIIA(3) IV A(DIVA20 I A

063 8437 83 2 2 IV ? 051. 3338 06 6 6 III 12, Q 032 77

39.57 2 2 IV AIIV A.75 HIEIIV

1 21007 3646 11 ? 1 20988 7946.83 100, z ? 952. 1969.69 1 20, Q 917 5268 11 1 5. G 41 A ... . 864 48

77.29 1 1, h (0) IV 868 6479.95 1 10 4 HI A.::::...

2 HI A10 III A2 IV A

tr HI A3 III A

709 8382 02 1 s 682 5083.56 2 2 IV A

IIV A

lOIVElOIVE100 III E75 HIE.......60 HIE

trIVAtrIV A8 V E

15 657. 8086.55 1 3 653 44

4294.77 8 1 651. 744305 71 10 7 622 72

14 09 60, Z 1 603 9820.73 50, Z 7 2 HI A 601. 4725.00 40, Z 6, n, 1 - 679. 80

48.63 1 6, n? 578. 5862.14 1 (O)IVA

(2) IV(DIVA(DIVA

(DIVA(2) HI A3 HI A(2) HI A(DIVA

(D III A2 III A(DIVA(DIVA5 HI A

3 III A4 HI A2 HI Ad?

573. 9264.60 6 1 . .- 493 8358.64 2 4 III A

2 III A

IIV AIIIIA60 III E1 III AtrIIIA

? 483. 0869.07 2 1 442. 78

69 64 1 1 431 6764.91 2 2 374.8374.46 40, Z 5 . ... :.. 361. 9675 18 1 4 307 8281.24 1 2 260.86

81.85 1 2 254 7184.80 6 8IVE?

2 IV A.6 231.92

89.60 2 ? 191. 184391. 12 1 1 189. 554400 38 30, Z 50 HIE

40 HIE

16 179 84

16.66 20, Z 10 100.3620 66 2 15 073 29

4431 36 3 4 V E 7 060 884642.55 2. 2 HI A

5 HI A

5 III

034. 0744.68 2 16 5 III A

(DIVA

026. 84

67 23 3 1 20014 4173.99 3 6 HI. 19974. 1478 98 1 IIV A

3 IV972. 23

92 94 2 2 938 1398.16 1 IIV A

3 IV

7 (2) III A

(2) IV

921. 17

4598 46 1 5 914. 224604. 72 1 (l)IVA

(O)IIIA(O)IIIA

8.... (2) IV A 908. 7909.53 1 888. 4709.95 1 1 „ . 874. 0810 41 40 10 VE

(D IV

871. 16

65.85 3 864.3770.40 16 15IVE. 1 847.4672 54 5, nl . . 1 818. 3775 53 1 1 780. 97

4680. 49 2, h._ 1 768. 58

4698. 30 2, E & H . - 20 10 HI 740.544706 97 3 2 732. 47

09.33 6 5 HI 5 2 HI 722. 8611.73 1 30 40 HI 717. 5713.86 1, p? 15 .. . - 10 HI 695. 82

14 36 1 D? 679. 3017.03 1.. .:::::::::: 76 125 II 673.5319.34 1. p? 60 . ... 80 II 665. 1720.82 ?...::::.:.-. (0) HI A

6 III50 40 II 658. 13

4728. 76 6 40 40 II 19652.68

Meggers] Arc Spectrum of Scandium

Table 1.

—

Scandium spectra—Continued69

MA Intensity andnotes

Intensity andclass

V \IAIntensity and

notesIntensity and

classV

5087. 12 30 10 IV? 19652.03649.12641.33631.42614. 97

605. 40598.09574. 11

567.63653.09

538.45473. 83366. 39356. 45333.06

315. 77279. 67260. 21

186. 62183.82

155. 84152. 98079.36

19012. 1718916. 33

913. 51

863. 05855. 79810. 59807.44

797. 60780. 87778.54772. 87750. 30

741. 68723.47717. 68711.03688. 85

687.42685. 36666. 34665. 16

661. 36

698. 31540. 58504.06458. 28457. 33

437. 25426. 13413. 14401. 14400.16

383.28380.64368. 51

356. 37352. 33

347. 45339.03326.02292. 52281.85

269. 16260.98236. 50227. 79

18218. 62

5514.2115.3920.5026.0626.35

26.8236.4341.0546.4049.68

60.4051.8462.2553.6753.98

56.5061.1064.8871.2479.75

91.345593. 395604. 1908.9010.12

23.7024.0131.0234.8240.99

46.3747.6049.5557.8958.35

61.7067.1669.0571.8084.21

86.846691. 336700. 1408.6211.76

17.3020.9524.0935.2036.85

39.3041.3664.4572.7475.32

5797. 605801. 3209.8411.6036.46

47.7349.0777.8380.6187.38

87.755894. 635918. 04

19.115928. 10

351

80 III 18129. 9487.87 2 126. 0689.89 10 8 IV..

f-:- loom... 109. 28

92 46 2 1 IV A?30 III

091 0696.73 16 1 .J 090.12

6099.22 25 40 III 752

10 VE 088. 586101 12 10 20 III 057 18

07.37 1 7 -43

3 IV 042. 1209.06 3 3 III 1 IV 024. 7212.86 3 4 III 014. 07

16 69 15 10 III 3 Oil 7333.67 2, h 2 007.0662 15 1, P? 3 . 005 7365.07 1. p? 5 001. 4571.05 2. +D . 18000. 12

75.68 1. D? 1 17991. 9685 37 ip? 3 977 07

6190. 61 2 10 4 III A 964. 935210. 52 10 20 IV 3 944 36

11.28 (O)IVA

(0) IV..

3 916.99

18.89 ? 12 15 IV A 879. 8519.67 ? 10 IV 5 873. 3039.81 15 2IVE

15 IV3 IIV 838. 85

58.33 12 1 823. 8784.97 2 tr IV A

10 IV

2 820 00

85.76 8 2 1 IV 776 965299. 90 1 1 775. 986301. 94 4 211 A 3 IIV A? 753. 86

14.68 1 tr IV AtrIVA.

IIVEtr IV A(0) IV

2:::::::::::::: 741.8816.57 1 15 . . 2 V E 722 48

18.35 3 5 4 IV 705. 5923.09 0. 3 IIV A

6 IV701. 74

23.75 1 . . 7 695. 6325.36 26 15 VE

2 V E669.54

31.77 6 3 IV A

tr IV A........8 IV

8 668. 11

34.22 2 1 trIVA.2VE

657. 6539.41 8 10 640.6441.06 10.. 8 IV 12. .- 2IVE

200 II634. 76

42.96 9, Q 10 II A60 III

100 .- 626. 2149.30 25 16 - 8VE 587. 7349.71 7, Q 15 II A

4 IV A8 III

75 150 II 579. 5960.30 6 ? (0) IV 566. 7265. 76 7 50 100 II 538 5866.09 40 60 III 20 15 III A

100 III A

15 III AtrIV

512. 5257.18 2 46 502.92

75.34 20 20 III 35

k::::::::::::

485. 936392. 08 25 30 III 474 785402. 72 1 .... 15 III A 465 19

16.12 6. 2 III 431. 3616.40 2 5. n. 1 426 35

22.30 1

' '

2 . . 2 IV AIIV A

418 9125.57 8 2 III 2 412. 6629.40 7 2 III 3, n, 1 342. 9132.94 2? 5, n, 1 318 0033.23 5 2 III 2, n,l 310 27

38.22 4 1 III A2 III

2 243 7539.03 6 3, n, 1 232. 6942.59 10 2 III 3 n, c 207 4246.19 30 20 III 3, n, 1 202. 2147.39 3 1 IV 1, n, 1 128 94

48.84 6, n, 1 095. 9351.34 15 6 III A

1 III AtrIV A2 in

6, n, 1 092 0156.21 3 2, n. 1 008. 3865.20 3 2, p? 17000. 3468.39 6 4 n i 16980 79

72.19 8 3 III 2 979 7274.64 2 . ... 3 (2) IV 959 9081.99 40 100 III

80 III2, n, 1 892. 81

84.61 30 5 trIVA 889 765487.37 1? - 2. n.f 16864. 15

70 Scientific Papers of the Bureau of Standards

Table 1.

—

Scandium spectra—Continued[Vol.SZ

XIA Intensity andnotes

Intensity andclass

p XIA Intensity andnotes

Intensity andclass

p

6931. 23 4 16855. 25828. 72795. 87776. 67769. 69

750. 70748.06694.28681. 91655. 57

614. 80602.02589. 68562. 22485.37

462.73461,43444.72362.28346. 12

281.30265.59259. 11246.29155. 61

143.07141.09128. 64096.85072.32

048.43022. 76021. 78

16006.7516996. 68

972.65964. 27936.53928. 56919.83

918.74908.53907. 90907.06886. 16

874. 20866.87854.34853.64843.74

816. 27811. 56787.87763.34756. 49

714. 54672.53629.53612.98600,17

588.12530.76508.59607. 61

504.17

480. 98436.06416.00412.74

15389. 99

6617.6725.6057.8768.0566.86

76.896598. 976600. 82

04. 60^ 09.98

17.9046.0454.3961.0190.69

91.166692. 836700. 4406.9314.60

17.6437.8839.4348.24

6786, 96

6817.1019.6129.6235.0337.58

50.4364.6774.3177.4081.10

85.3089.82

6890. 93

6936.7761.62

63.1180.6185.49

6990. 707005. 51

25.7035.7649.3872.3982.40

7094. 41

7120. 4330.6138.1341.18

69.1380.69

7189. 74

7233. 1440.27

67.567275. 567300. 657323. 787332. 53

7346. 947621. 74

24.1163.96

7563. 56

1, p? 1533 S. 6840 58 2 6 +n? (3) IV? 320. 0452 20 6 .'.III... 3 244. 6559.01 1, n? 2

3, n, 1

16 IV.... 244.2361.49 6 .- Tiv":::::::::: 223.80

68.25 7 3, n, c 202.8869.19 5 3 IV 1, p? 149. 7088 42 10 20 IV 2, n, c. 145.44

6992 86 10 136. 796002. 34 2, p? 4, n, 1 124. 47

17 07 4, n, 1 2, n, 1 106. 3721.70 ?. (0) IV 2, n, 1....

'

044. 6726.18 7 15 IV . . . 3, n, 1 . 023.6336.17 10, n, 1 3, n, I 15008. 6064.31 6, n, 1 1, n? 14942, 26

72.65 4, n, 1 2, n? 941.0073.13 1, p? 1 .,. „ 937.25

6079 30 6, n, 1 2, n, 1 920. 286109. 93 5, n, 1 3, n? 908.0716.97 5, n, 1 2 888.82

40.32 2, n,l 3 882.0846.26 4 (3) IV A 10 837.3848.70 2, nVf.:::::::: 7 833.9663.93 2, n,l 2... 814.6088.09 2, p? 2, p? 730. 10

92.90 2, n, 1 10 664, 9593.66 2 (3) II A 20 669.77

6198 44 4 16. 638.296210. 68 30j G- 200 1 A. 25 626.4820.16 1, p? 2, h, p? . 621. 03

29.42 1, p? 2, n? 593.6039.40 8 . . ..:... 20 II A

100 I A8 VE

2;h.... 563,5439.78 15, G.. 3, h 542.9146.64 20 3 h 536,3849.96 10 15 IV . 4, h 528. 56

68.97 20, G 100 1 A10 IV .

6, h 519.7062.26 8 7, h .. 510. 1773.16 ? (0) IV 3, h- 607.8376.30 9, G. 15 II A. 2, h 411.9679.74 15. 3, h .. 360. 62

80.17 3 3, h, p?... 367. 44

84.20 4 1, n? 321, 4584.45 ? . 5 IV 3, h 311. 4584.78 6 5, n, 1 300, 7893.05 4 (2) IV 3, n, 1 270.64

6297. 79 ? (0) IV 3. n. 1 229. 546300. 70 6 4 n 1 209. 2105.68 40, G 4001 A.

20 1 A2 n? . .... . 181, 75

06.00 10 2, n, 1 135, 6009.90 15 3, n, 1 115, 62

20.86 7 3, n?. 091,7322.74 2 2. h 040. 2332.23 1 (1) IV IS:::::::::::

__.-.020. 19

42.08 1 6 ._ 14005. 42

44.84 3 -. 5 II A 2. D?. 13999. 44

61.78 1, p? 8 944. 8678.83 8,G ..." 40 I A „ 3, h, n? 922.40

6396. 38 2 IV 2, h, n? 904.876403. 16

3, n?2IV_...(1) IV

2, h, n? 821. 4508.42 2, h, n? 807. 84

33.37 10, Q 50 I A 6 774.9837,06 2, n, 1 4, h . 740.8846 26 2,n,l

2, h ..3 o- 693,64

46.67 2 „. 650, 4048.10 2 1 II A 1 . 634,11

57.76 2, n 1 1 607. 3676.55 1, n,l...II.I„ 4, h 291,1585.40 3, n, 1... 7 286,96

86.36 ? (O)IVA? 6 :::::::::.... 234. 456496. 94 3, n.i. :..:::.. . . 13217.07

Mengera] Arc Spectrum of Scandium

Table 1.

—

Scandium spectra—Continued71

XIA Intensity andnotes

Intensity andclass

y XIA Intensity andnotes

Intensity andclass

p

7674.44 7 13198. 67181. 20124. 15

13041. 5012987. 23

937.93933. 51

919. 37914. 34911.54

899. 07895. 13864.72841. 40825. 74

819. 05816. 27781.54766. 61

12752. 45

7848. 558003.2706.4017.83

8043.44

8178.9281.3283.3694.87

8196. 98

8239. 058241. 13

8408. 018644.48

2 12737. 717584. 48 3 2 491. 467617. 45 5 2 486.58

65.72 4 3 468. 777697. 76 10 1 429.04

7727. 09 2 2, Cu? 223.2029.73 7 1 219. 6038.18 2 2 216. 5641.20 20 4 199. 4642.82 1 3 ::::::::::::::': 196. 26

50.37 4 1 133. 9952.72 3 . . 4 12130. 9371.06 4 2, h 11890. 1685.17 6 11564. 9094.68 5

7798. 75 17800. 44 1521.64 6 .30.78 1

7839. 47

IV. BIBLIOGRAPHY

1. Meggers, B. S. Sci. Papers (S312), 14, p. 371; 1918.

2. Meggers and Kiess, B. S. Sci. Papers (S324), 14, p. 637; 1918.3. Burns, Meggers, and Merrill, B. S. Sci. Papers (S329), 14, p. 765; 1918.4. MerriU, B. S. Sci. Papers (S345), 15, p. 251; 1919.

6. Kiess and Meggers, B. S. Sci. Papers (S372), 16, p. 51; 1920.6. Walters, B. S. Sci. Papers (S411), 17, p. 161; 1921.

7. Kiess, B. S. Sci. Papers (S421), 17, p. 318; 1921.

8. Kiess, B. S. Sci. Papers (S442), 18, p. 201; 1922.

9. Kiess, B. S. Sci. Papers (S466), 18, p. 695; 1923.

10. Meggers, B. S. Sci. Papers (S499), 30, p. 19; 1925.

11. Kiess, B. S. Sci. Papers (S548), 22, p. 47; 1927.

12. Meggers, B. S. Sci. Papers (S499), 30, p. 19; 1925.

13. Meggers and Burns, B. S. Sci. Papers (S441), 18, p. 191; 1922.14. Lockyer and Baxandall, Proc. Roy. Soc, 74, p. 538; 1905.15. Fowler, Phil. Trans. A., 309, p. 47; 1908.

16. Exner and Haschek, Die Spectren der Elemente bei normalem Druck.17. Eder and Valenta, Wien, Ber., 119, II a, p. 519; 1910.18. Crookes, Proc. Roy. Soc, 95, p. 438; 1919.

19. Pina, Anal. Soc. Esp. Fis. Quim., 34, p. 41; 1926.

20. Ireton, Trans. Roy. Soc. Can., 18, p. 103; 1924.

21. Smith, Proc. Nat. Acad. Sci., 13, p. 65; 1927.

22. King, Astrophys. J., 54, p. 28; 1921.

23. Goudsmit, van der Mark ^d Zeeman, Roy. Acad. Sci. Amsterdam, 33, p.975; 1924.

24. Gieseler and Grotrian, Zeitschr. Phys., 35, p. 361; 1924.25. Russell and Meggers, see forthcoming paper.

Washington, March 5, 1927.\