Tables of Spectral-Line Intensities Part I - Arranged by Elements

409 Pages·1975·1.27 MB·English

by  William F. Meggers

Parti
U.& DEPARTMENT Of / National Bureau of Standards
Tables of
Spectral-Line Intensities
Arranged by Elements

W, F. Meggers prepares to measure one of the spectrograms on which these tables of spectral line intensities are based.
Tables of Spectral-Line Intensities
Part I - Arranged by Elements
Second Edition
William F. Meggers* Charles H. Corliss and
Bourdon F. Scribner
Institute for Basic Standards
National Bureau of Standards
Washington, D.C. 20234
The intensity, character, wavelength, spectrum, and
energy levels of 39 000 lines between 2000 JL and
9000 A observed in copper arcs containing
0.1 atomic percent of each of 70 elements.
(Supersedes NBS Monograph 32, Parts I and II
and its Supplement)
U.S. DEPARTMENT OF COMMERCE
NATIONAL BUREAU OF STANDARDS, Richard W. Roberts, Director
Issued May 1975
Library of Congress Cataloging in Publication Data
Meggers, William Frederick, 1888-1966.
Tables of spectral-lines intensities.
(National Bureau of Standards Monograph 145)
ffThe intensity, character, wavelength, spectrum, and energy
levels of 39,000 lines between 2000 A and 9000 & observed in
copper arcs containing 0.1 atomic percent of each of 70
elements."
"Supersedes NBS Monograph 32, Parts I and II, and its
Supplement."
CONTENTS: Pt. 1. Arranged by elements. Pt. 2.
Arranged by wavelengths.
Supt. of Docs. No.: C13.44:145.
1. Spectrum analysis Tables, etc. L Corliss, Charles H.,
joint author. Tables of spectral-line intensities. II.
Title. III. Series: United States. National Bureau of
Standards. Monograph 145.
QC100.U556 No. 145 [QC453] 389©.08s [535©.84] 74-16256
National Bureau of Standards Monograph 145
Nat. Bur. Stand. (U.S.), Monogr. 145, 403 pages (May 1975)
CODEN: NBSMA6
U.S. GOVERNMENT PRINTING OFFICE
WASHINGTON: 1975
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402
(Order by SD Catalog No. C 13.44:145/1). Price $8.55 (Part I); $6.80 (Part II)
Stock Number 0303-01337 (Part I); 0303-01338 (Part II)
Preface
A second edition of the NBS Tables of Spectral-Line Intensities (Part I. Arranged by Elements
and Fart II. Arranged by Wavelengths) has been prepared. New classifications have been provided
for 8500 previously unclassified lines, improved wavelengths are given for about 9000 lines and some
revision of the intensity scale has been made. (Supersedes NBS Monograph 32. Parts 1 and II and its
Supplement.)
Key words: Classification of spectral lines: intensities of spectral lines: spectral-line intensities: tables
of spectral-line intensities: wavelengths of spectra] lines.
This new edition of the NBS Tables of Spectral-Line Intensities incorporates three improve
ments on the original edition of 1961. In the original edition only about 25 000 of the 39 000 lines in
the tables had been classified. In the ensuing thirteen years, about 8500 more lines {chiefly rare-
earths) have been classified and the new classifications are here incorporated.
Furthermore in the course of spectroscopic research during that period, many spectra have
been remeasured. About 9000 improved wavelength values have been adopted here. Many of the
new values are accurate to somewhat better than two decimal places but in most cases there
remains some uncertainty in the third place. We have therefore printed only twro decimal places in
this edition.
The third improvement to be found in this edition is in the intensity scale. Three changes have
been made. The calibration of the region below 2450 A, which was published by Corliss [1967], has
been incorporated in the new edition. Secondly, a slight error in the original reduction of the
intensity data from the overlapping regions of the plates has been corrected. In the original reduc
tion the duplicate observations In the overlapping regions were simply averaged. This was a
theoretically correct procedure since the observations had already been normalized to the intensity
scale of the copper matrix. However, it wras observed that this normalization did not produce
identical scales on each plate. A more practical procedure would have been to have adjusted each
plate to a common scale determined by the mean intensity level of all the plates. This wras pointed
out by J. L. Tech [1971] who has now applied this correction to all of the complex spectra in the
tables. The elements with less than 100 lines (simple spectra) remain uncorrected for this relatively
minor error because there are not enough lines in the overlapping regions in determine correction
factors.
Finally, the whole scale of relative intensity numbers has been multiplied by ten to eliminate
numbers less than unity. The intensity numbers now range from 1 to 90 000.
For the convenience of the user, the tables are presented in two separate parts, in the same
way as the original edition. Part 1 is arranged by element in alphabetic order of chemical name.
In Part II all observed lines are consolidated in a single table arranged in order of increasing
wravelength and in a supplementary table of selected strong lines.
The values of ionization potentials for many of the elements are taken from the compilations
of C. E. Moore but those for the lanthanides, actinides and Hf are taken from the compilation of
W. C. Martin, Lucy Hagan, Joseph Reader and Jack Sugar (J. Phys. Chem. Ref. Data, Vol. 3,
No. 3, 1974). The values of atomic weights are taken from the 1969 Report of the International Com
mission on Atomic Weights.
References
Corliss, C. H. (1967), Revision of the NBS Tables of Spectral-Line Intensities below 2450 A. NBS
Monograph 32 Supplement.
Tech, J. L. (1971), A High-Dispersion Spectral Analysis of the Ba II Star HD 204075 (f Capricorni).
NBS Monograph 119.
Charles H. Corliss
Washington. D.C., April 25,1974
iii
Contents
Page
Preface to the Second Edition iii
1. Introduction __________ v
2. Experiments __________ vii
3. Results._______________ xii
4. References ____________ xiv
List of Tables
Chemical Sym Atomic Melting Boiling Page Chemical Sym Atomic Melting Boiling Page
element bol number point * point * element bol number point * point *
K K K K
Al 13 933.2 2793. 3 Neodymium Nd 60 1289. 3335. 159
Antimony Sb 51 904. 1860. 4 Nickel __________ Ni 28 1726. 3187. 172
As 33 subl. 885. 5 Niobium Nb 41 2740. 5017. 175
Barium Ba 56 1002. 1900. 6 Osmium Os 76 3323. 4500. 188
Beryllium _ _ Be 4 1560. 2745. 8 Palladium _______ Pd 46 1825. 3237. 197
Bi 83 544.5 1837. 9 Phosphorus ____ _ P 15 317.3 530. 198
Boron B 5 2450. 4075. 10 Paltinum Pt 78 2043. 4097. 199
Cadmium Cd 48 594. 1040. 11 Potassium. _ K 19 336.4 1031. 202
Ca 20 1112. 1757. 12 Praseodymium Pr 59 1204. 3785. 203
C 6 subl. 4100. 13 Re 75 3453. 5960. 216
Ce 58 1071. 3699. 14 Rhodium _ _._ Rh 45 2239. 4000. 225
Cs 55 301.8 955. 36 Rubidium ___ _ Rb 37 312. 967. 230
Chromium Cr 24 2130. 2945. 37 Ruthenium Ru 44 2700. 4390. 231
Cobalt __________ Co 27 1768. 3201. 45 Samarium. __ _ Sm 62 1345. 2064. 240
Copper Cu 29 1356.5 2839. 52 Scandium Se 21 1812. 3104. 254
Dysprosium^. Dy 66 1682. 2835. 53 Se 34 494. 958. 259
Erbium _ _ . __ Er 68 1795. 3136. 65 Silicon Si 14 1685. 3540. 260
Europium _ _ . Eu 63 1090. 1870. 76 Ag 47 1234. 2436. 261
Gadolinium _ _ Gd 64 1585. 3539. 82 Sodium Na " 11 37LO 1156. 262
Gallium __ __ _ Ga 31 302.9 2520. 95 Strontium. ___ __ Sr 38 1047. 1649. 263
Germanium.. ___ Ge 32 1210.4 3107. 96 Ta 73 3250. 5638. 264
Gold ____________ Au 79 1336. 3081. 97 Te 52 723.0 1261. 276
Hafnium _ ___ Hf 72 2500. 4876. 98 Tb 65 1630. 3496. 277
Holmium _ . Ho 67 1743. 2968. 105 Tl 81 577. 1760. 291
Indium. _ _ In 49 429.3 2343. 114 Th 90 2028. 5061. 292
Iridium _ Ir 77 2727. 4662. 115 Tm 69 1818. 2220. 311
Iron _ , _ Fe 26 * 1809. 3135. 121 Tin__-_______ ___ Sn 50 505.0 28%. 319
Lanthanum La 57 1193. 3730. 128 Titanium Ti 22 1943. 3562. 320
Lead _ _ ____.. Pb 82 600.6 2023. 134 W 74 3680. 5828. 329
Lithium Li 3 453.7 1597. 1 3^ U 92 1405. 4407. 340
Lutetium Lu 71 1936. 3668. 136 Vanadium V 23 2175. 3682. 357
Magnesium ___ Mg 12 922. 1363. 139 Yb 70 1097. 1467. 367
Manganese Mn 25 1517. 2335. 140 Yttrium, __ _ Y 39 1799. 3611. 372
Mercury Hg 80 234.3 629.7 144 Zinc Zn 30 692.6 1184. 377
Molybdenum Mo 42 2890. 4S80. 145 Zr 40 2125. 4682. 378
* Melting and boiling points are quoted from American Institute of Physics Handbook, 3rd ed., New York, 1969.
IV
Tables of Spectral-Line Intensities Part I
Arranged by Elements
The relative intensities, or radiant powers, of 39 000 spectral lines with wavelengths between
2000 and 9000 Angstroms have been determined on a uniform energy scale for seventy chemical
elements. This was done by mixing 0.1 atomic percent of each element in powdered copper, press
ing the powder-mixture to form solid electrodes which were burned in a 10 ampere, 220 volt direct-
current arc, and photographing the spectra with a stigmatic concave grating while a step sector
was rotating in front of the slit. The sectored spectrograms facilitated the estimation of intensities
of all element lines relative to copper lines which were then calibrated on an energy scale provided
by standardized lamps, and all estimated line intensities were finally adjusted to fit this calibration.
Comparisons with other intensity measurements in individual spectra indicate that the National
Bureau of Standards spectral-line intensities may have average errors of 20 percent, but first of
all they provide uniform quantitative values for the seventy chemical elements commonly deter
mined by spectrochemists. These data are presented by element in part I, and all 39 000 observed
lines are given in order of wavelength in part II.
Key words: Classification of spectral lines; intensities of spectral lines; spectral-line intensities; tables
of spectral-line intensities; wavelengths of spectral lines.
1. Introduction
Spectrochemistry was born a century ago when Unfortunately during this past century very little
Kirchhoff and Bunsen [I]1 definitely demonstrated progress has been made in assigning uniform quanti
that chemical elements were uniquely identified by tative intensity values to spectral radiations. The
spectral radiations, or lines as seen in a spectroscope great bulk of spectral observations have been made
provided with a slit. This led immediately to the photographically because photographic emulsions
identification of many chemical elements in the sun provide detailed, permanent records of spectra not
and to the discovery of several new elements, but only in the visible but also in the invisible ultraviolet
no quantitative chemical analyses were made until and infrared regions. But even if the light source is
much later. reproducible and standardized it is not easy to
In 1874, Lockyer [2] stated that "while the qualita evaluate the spectral efficiencies of spectrographs
tive spectrum analysis depends upon the positions of and photographic emulsions so the usual procedure
the lines, the quantitative analysis depends not upon has been to make subjective visual estimates of
their position but upon their length, brightness, thick relative intensities of spectral lines on an arbitrary
ness, and number as compared with the number scale based on the relative blackness and/or width of
visible in the spectrum of a pure vapor". Thus, posi spectral-line images appearing on a developed photo
tion (or wavelength) and brightness (or intensity) are graphic plate. Consequently, in thousands of indi
recognized as being the two most important proper vidual papers and in numerous comprehensive
ties of spectral lines; wavelengths identify chemical compilations of spectral data we find only qualitative
elements and intensities indicate the concentrations data on intensities which may have some meaning
of identified elements in mixtures or chemical for adjacent lines in a given spectrum but none at
compounds. all when comparing widely spaced lines, or lines of
During the past century there has been spectacular different spectra of the same element or of different
improvement in the accuracy of spectral wavelength chemical elements.
determinations; the early ones were limited to 3 or In the beginning, most intensity data were reported
4 figures, the later use of diffraction gratings and on an arbitrary scale of 10 steps, weak lines being
wavelength standards permitted the specification assigned an intensity of L and the strongest line
of 5 or 6 figures. Since 1900 the application of inter intensity 10. Even as late as 1945 extensive new
ferometers and better gratings has refined many spectral tables prepared by Gatterer and Junkes [3]
wavelengths to 7 figures, and recently some 8-figure displayed estimated intensities on this limited 1 to
values of wavelength standards have been provided. 10 scale. Since 1910 some spectroscopists have
1 Figures in brackets indicate the literature references on page xiv. arbitrarily expanded this arbitrarily compressed
scale. For example, in the very extensive spectral Our method of deriving line intensities from arc
tables published by Exner and Haschek [4| the spectra of elements diluted in copper wras recently
estimated intensities range from 1 to 1000. In wave adopted by Alien [14, 15J to obtain oscillator
length tables compiled by Twyman and Smith [5| strengths of some radiations from 3200 to 5400 A
the maximum intensity is 20, in the compilation of representing nine elements.
Kayser and Ritschl [6| estimated intensities rise to
At various times since 1932 we have photographed
4000, and in the well-known M.I.T. Wavelength
the arc spectra of 70 chemical elements diluted in
Tables [7| they soar to 9000. The most recent com
silver or in copper, and determined the line intensi
pilation of Tables of Spectrum Lines by Zaidel,
ties of the diluted elements relative to selected lines
Prokofev, and Raiskii [8| quotes data from the
of the matrix. An energy calibration of the latter
M.I.T. Tables and more modern sources but adds
finally led to physical intensities of 39,000 spectral
nothing new on spectral line intensities.
lines representing 70 elements, all on the same
In or about the year 1925. microdensitometers
energy scale. These experiments and results are
were developed for the purpose of quantitative
based on the following propositions, regarded as
measurement of relative intensities among related
fundamental for the quantitative description of
lines in multiplets to test the sum rules derived from
residual spectra of diluted elements excited in
the quantum theory of spectral structure, but no
ordinary d c arcs.
general applications were made. Since then thou
sands of spectrochemists have applied micro
1. The limiting detect ability of any line is de
densitometers to quantitative chemical analyses by
fined as the atomic concentration that ensures posi
calibrating intensity ratios of analysis- and internal-
tive detection of the line. This limit is determined
standard lines but such measurements have con mainly by unavoidable background on a fully ex
tributed nothing to the basic data on spectral line
posed spectrogram. The spectrum of an arc burning
intensities. Likewise, with few exceptions, the
in air consists of discrete lines due to atoms, and of
modern substitution of electronic photodetectors for
more or less extensive band systems from transient
photographic emulsions has added nothing to our
compounds (usually monoxides), all superposed on a
knowledge of true line intensities over long ranges
continuous background arising from thermal radia
of different spectra of many chemical elements.
tion of incandescent oxides, from transitions in the
How may one hope to obtain, with a reasonable
continuum, and possibly from scattered light. This
amount of labor, quantitative intensity data on the
background sets a limit to the exposure for faint
same scale for thousands of spectral lines represent
lines that may be given by any actual spectrograph.
ing practically all of the metallic elements? A hint
If this were not true, the exposure could be in
was given in 1874 by Lockyer [2] who observed that
creased indefinitely to compensate for unlimited
tkthe lines of any constituent of a mechanical mixture
reduction in concentration, and detectability would
disappeared from the spectrum as its percentage
always be infinite. Faint lines are not recorded by
was reduced." Acting on this suggestion, Hartley [9],
underexposure, and they cannot be recognized on a
in 1884. began to study the spark spectra of metals
very dense background produced by overexposure.
in solutions with concentrations of 1 percent, 0.1
In order to guarantee positive recognition and un
percent. 0.01 percent, and 0.001 percent, and pro
ambiguous chemical identification a spectral line
posed a method of quantitative spectrochemical
should be sufficiently well defined to permit accurate
analysis based on the lines that could be detected
wavelength measurement, Experience showrs that
at each dilution. Similar studies were later made by
the minimum photographic density that meets this
Pollok and Leonard |10|. by de Gramont [111. and
requirement is of the order of 0.05 above that of the
by Lowe [12], all showing that with progressive
background.
dilution of an element its spectral lines weakened
and vanished until only the most sensitive line re 2. The limiting detectability of any element in an
mained to reveal its presence. In all these works the arc depends on the matrix in which the element finds
principle of quantitative spectrochemistry appeared itself. There is no doubt that in the conventional arc
to rest on the number of lines detectable rather than relative volatilities of the chemical elements as well
on their individual intensities. Casual observation as relative ionization potentials affect the relative
must have shown lines of equal strength in spectra strengths of their mixed spectra. In general, the
of solutions differing 1000 fold in concentration but elements with high-vapor pressure and/or low-
no one mentioned it. It is difficult to understand why ionization potential will be favored in spectral
these early studies of residual spectra in quantitively excitation, but elements with either high or low
prepared mixtures or solutions did not suggest volatility may be underestimated if not uniformly
a method for obtaining physical intensities, but present during the exposure, and easily ionized
it is a fact that before our work had begun no one had elements may appear less sensitive because of more
attempted to express spectral line intensities as complete ionization. In this connection it must be
directly proportional to the number of radiating noted that large differences in apparent detectabil
atoms or concentration of the element. The present ity are possible if concentrations are expressed in
monograph reports such an attempt f!3|. relative weights instead of numbers of atoms. Thus,
VI