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Absorption spectrum of Pm+3 in D2O, DCI
Notes
303
in the copper compound at a temperature well below the maximum used for the post irradiation heating"' (240°C) I~ut no abnormality in retention was observed. it can he seen from the table that the difference in retention between the ~,- and/~-form~ of zinc phthalocyanine is slight, when determined by the method of complete solution in strong sulphvric acid. There are large differences in apparent retention however, when dilute suiphuric acid is used to extract the recoil ~ Z n . This is probably due to differences in particle size as it is known that the ~-forms have good covering power as pigments but the ~-forms are useless. Samples were examined by infra-red spectroscopy to determine their form,--previous work"' was carried out with the zinc and copper in the ',-form. The ~-zinc compound for irradiation was prepared from the ~- by boiling in acetone for 8 hr and the copper ~-form, by boiling the ~-modification in cyclohexanol for 4~ hr. ~' Radioactive ~sZn was determined from the intensity of 1.17 MeV ~,-ray peak by scintillation spectrometry, after ~Na present in small amount as impurity had decayed. l would like to thank Mr. P. J. FYDELOR for the infra-red analyses. G. B. Coog Isotope Division A.E.R.E., Harwell Didcot, Berks
A b s o r p t i o n s p e c t r u m o f P m +a in D ~ O , D C I (Received 25 March 1960)
THREE groups of investigators have already reported the general structure of the solution absorption spectrum in Pm ~a between 3000 and 10,000 A. ",s,~ In every case reported, the instrument employed was either a ModeI-LD or Model-DU Beckman spectrophotometer, and the largest amount of material handled was 5 rag. (a)
/\ (b) C
(c)
Wave
length
(A }
FIG. l.--Solution absorption spectrum of 0-039 .M Pm+s in 0.023 M DCI (98% DsO). (a) 6700 to 8300 A; (b) 6300 to 4700 A; and (c) 4700 to 3000 ~. We wish to report the absorption spectrum of Prn +a in 0.023 M DCI (98 ~o DsO) from 2600 to 19,000~ under higher resolution than previously reported. Using a Cary Model-14 recording spectrophotometer, we have observed additional structure in the ultra-violet region. Molar extinct~o,~ ql~ G. W. PARKERand P. M. LANTZ, J. Amer. Chem. Soc. 72, 2834 (1950). is) W. F. MEGGERS,B. F. SCRInNERand W. R. BOZMAN,J. Res. Nat. Bur. Stand. 46, 85 (1931). 4,) D. S. STEWART,Argonne National Laboratory Report, ANL 4812 0956).
304
Notes
coefficients were calculated for all peaks from 2600 to 8233/~. No additional peaks were observed from 8233 to 19,000A. An crnission-Spectmm analysis of P m +8 in 1 M HC1 solution obtained from ()ak Ridge National Laboratory indicated impurities of Nd, Sm, AI, Ca, and Am. Purification of 60 mg of Pin +8 was carried out by the use of a heated (87°C) Dowex-50 cation-exchange column with at-hydroxybutyrie acid as eluting solution, c~> After all other rare-earth impurities were separated from P m +8, th~ column was converted to a 12 N HCI column and P m +a was separated from actinide impurities.~ o
TAeI~ 1.--AesoRFrIoN P~AKS OF Pm +s IS 0.023 M DCI (98 ~o DsO) 2, Wavelength
ofpeak 2610 3074 3126 3153 3200 3281 3329 3440 3870 4015 4226 4496 4583 4933 5448 5476 5679 5750 5905 6261 6838 6980 7019 7152 7347 7824 8010 8057 8233
Band width at half max.
Slit width
(A)
(mm)
-2690 3056-3081 3113-3139 3147-3160 3187-3213 3268-3294 3316-3342 3413-3460 3845-3890 4000-4057 4200--4250 4472--4520 4566--4600 4890-4986 5431-5470 5470-5502 5638-5700 5726-5760 5879-5929 6226-6300 6786-6886 6962-7000 7000-7036 7128-7176 7272-7400 7725-7872 7974-8046 8046-8080 8200-8245
0.080 0.075 0.061 0.061 0.061 0.061 0-061 0.061 0.030 0.021 0.017 0.016 0.015 0.013 0.012 0.012 0.013 0-013 0.013 0.019 0.048 0.069 0.071 0.075 0.13 0.40 0.52 0.52 0.71
e, molar extinction coefficienta
0.32 0.77 0.31 2-53 4.96 4.73 0.39 0-21 0-51 0.20 0.41 0.69 1.41 3-40 3.33 3.77 0.64 0-23 0.45 2.13 2.14 2.54 0.36 3.05 1.54 0.85 0.74 0.24
(No other absorption peaks were seen to 1.89 p) ° Log (lo/I)= A = tbc, where A is the absorbance,8 is in litres × cm-x × moles-x, b is the cell path length --2.001 cm, and c is in moles/l.
The PmCls solution was then taken to complete dryness under a heat lamp, and 30 ml of DCI, D 2 0 solution added. The drying procedure was again repeated, and again new D20, DC1 solution added, giving a final solution of PmC18 in D~O, DC1. The solution used in the absorption cells was analysed before and after each run. The concentration of Pm +8 was determined by 47r beta counting, and the chloride concentration by the Volhard ~*) R. M. DIAMOND, K. STREET,JR. and G. T. SEABORG,,Jr, A m e r . Chem. Soe. 76, 1461 (1954).
Notes
305
method. The amount of H,O in the Pm+* sample was obtained by comparison with known solutions of HIO in the DtO stock. One sample contained 30.0 mg Pm ~s per 3.23 mi 0.023 M DCI (98" ~ DtO). The Cary 14 spectrophotometer was calibrated at the fa~ory with an AH4 Hg arc. The Nd +~ and Am +s standards were run in this laboratory in order to check the absolute values of peak wavelengths. The calibration results indicated the instrument to be correct to 1.5 • in the region from 2700 to 4900 A and 2 A from 4900 A to 2/~. The resolving power of the monochromator is about 1.0 ~ in the ultra-violet and vbible ranges and about 3-0 ~ in the near infra-red. The wavelength ~ale b reprodt~ible to 0.5 A. Table I includes corrected wavelength values. The uncertainty in peak locations is --<2A. Slit widths and molar extinction coeff~ients, e. are also given. The Pm+j solution spectrum was compared with solution spectra of Eu* ~, Nd , s Sin" ~, and Am' ~. No trace of the rare-earth ions was ohserved. A trace of Am ~s was detected by a-assay (0.06 mg/ml). ConNquently, the Am ~* peaks at 5033 and 8152 A were subtracted from the promethium spectrum and the remaining peaks taken as Pm+s peaks. The solution absorption spectrum is shown in Fig. 1. Since additional peaks are not obey'veal from 0.8 to i.9 t~. the groundstate multiplets, hi, to ~1~, should be ~.,parated by less than 5400 cm-t The group of peaks around 8000 A are probably due to tmmitions from s14 to the SF and ss multiplets. However, an analysis of the Pro-* spectrum is best undertaken by studying the ion in a solid matrix. Such studies have already begun?~j
Lawrence Radiation Laboratory University of California Berkeley, California
J. B. GRUeEa J.G. CONWAY
is~ j. G. CoNw^v and J. B. Gl~uel~lt,LuminescenceSpectrum of PreCis, UCRL-9042(1960~: J. Chem. Phys. 32, 1586 0960).
303
in the copper compound at a temperature well below the maximum used for the post irradiation heating"' (240°C) I~ut no abnormality in retention was observed. it can he seen from the table that the difference in retention between the ~,- and/~-form~ of zinc phthalocyanine is slight, when determined by the method of complete solution in strong sulphvric acid. There are large differences in apparent retention however, when dilute suiphuric acid is used to extract the recoil ~ Z n . This is probably due to differences in particle size as it is known that the ~-forms have good covering power as pigments but the ~-forms are useless. Samples were examined by infra-red spectroscopy to determine their form,--previous work"' was carried out with the zinc and copper in the ',-form. The ~-zinc compound for irradiation was prepared from the ~- by boiling in acetone for 8 hr and the copper ~-form, by boiling the ~-modification in cyclohexanol for 4~ hr. ~' Radioactive ~sZn was determined from the intensity of 1.17 MeV ~,-ray peak by scintillation spectrometry, after ~Na present in small amount as impurity had decayed. l would like to thank Mr. P. J. FYDELOR for the infra-red analyses. G. B. Coog Isotope Division A.E.R.E., Harwell Didcot, Berks
A b s o r p t i o n s p e c t r u m o f P m +a in D ~ O , D C I (Received 25 March 1960)
THREE groups of investigators have already reported the general structure of the solution absorption spectrum in Pm ~a between 3000 and 10,000 A. ",s,~ In every case reported, the instrument employed was either a ModeI-LD or Model-DU Beckman spectrophotometer, and the largest amount of material handled was 5 rag. (a)
/\ (b) C
(c)
Wave
length
(A }
FIG. l.--Solution absorption spectrum of 0-039 .M Pm+s in 0.023 M DCI (98% DsO). (a) 6700 to 8300 A; (b) 6300 to 4700 A; and (c) 4700 to 3000 ~. We wish to report the absorption spectrum of Prn +a in 0.023 M DCI (98 ~o DsO) from 2600 to 19,000~ under higher resolution than previously reported. Using a Cary Model-14 recording spectrophotometer, we have observed additional structure in the ultra-violet region. Molar extinct~o,~ ql~ G. W. PARKERand P. M. LANTZ, J. Amer. Chem. Soc. 72, 2834 (1950). is) W. F. MEGGERS,B. F. SCRInNERand W. R. BOZMAN,J. Res. Nat. Bur. Stand. 46, 85 (1931). 4,) D. S. STEWART,Argonne National Laboratory Report, ANL 4812 0956).
304
Notes
coefficients were calculated for all peaks from 2600 to 8233/~. No additional peaks were observed from 8233 to 19,000A. An crnission-Spectmm analysis of P m +8 in 1 M HC1 solution obtained from ()ak Ridge National Laboratory indicated impurities of Nd, Sm, AI, Ca, and Am. Purification of 60 mg of Pin +8 was carried out by the use of a heated (87°C) Dowex-50 cation-exchange column with at-hydroxybutyrie acid as eluting solution, c~> After all other rare-earth impurities were separated from P m +8, th~ column was converted to a 12 N HCI column and P m +a was separated from actinide impurities.~ o
TAeI~ 1.--AesoRFrIoN P~AKS OF Pm +s IS 0.023 M DCI (98 ~o DsO) 2, Wavelength
ofpeak 2610 3074 3126 3153 3200 3281 3329 3440 3870 4015 4226 4496 4583 4933 5448 5476 5679 5750 5905 6261 6838 6980 7019 7152 7347 7824 8010 8057 8233
Band width at half max.
Slit width
(A)
(mm)
-2690 3056-3081 3113-3139 3147-3160 3187-3213 3268-3294 3316-3342 3413-3460 3845-3890 4000-4057 4200--4250 4472--4520 4566--4600 4890-4986 5431-5470 5470-5502 5638-5700 5726-5760 5879-5929 6226-6300 6786-6886 6962-7000 7000-7036 7128-7176 7272-7400 7725-7872 7974-8046 8046-8080 8200-8245
0.080 0.075 0.061 0.061 0.061 0.061 0-061 0.061 0.030 0.021 0.017 0.016 0.015 0.013 0.012 0.012 0.013 0-013 0.013 0.019 0.048 0.069 0.071 0.075 0.13 0.40 0.52 0.52 0.71
e, molar extinction coefficienta
0.32 0.77 0.31 2-53 4.96 4.73 0.39 0-21 0-51 0.20 0.41 0.69 1.41 3-40 3.33 3.77 0.64 0-23 0.45 2.13 2.14 2.54 0.36 3.05 1.54 0.85 0.74 0.24
(No other absorption peaks were seen to 1.89 p) ° Log (lo/I)= A = tbc, where A is the absorbance,8 is in litres × cm-x × moles-x, b is the cell path length --2.001 cm, and c is in moles/l.
The PmCls solution was then taken to complete dryness under a heat lamp, and 30 ml of DCI, D 2 0 solution added. The drying procedure was again repeated, and again new D20, DC1 solution added, giving a final solution of PmC18 in D~O, DC1. The solution used in the absorption cells was analysed before and after each run. The concentration of Pm +8 was determined by 47r beta counting, and the chloride concentration by the Volhard ~*) R. M. DIAMOND, K. STREET,JR. and G. T. SEABORG,,Jr, A m e r . Chem. Soe. 76, 1461 (1954).
Notes
305
method. The amount of H,O in the Pm+* sample was obtained by comparison with known solutions of HIO in the DtO stock. One sample contained 30.0 mg Pm ~s per 3.23 mi 0.023 M DCI (98" ~ DtO). The Cary 14 spectrophotometer was calibrated at the fa~ory with an AH4 Hg arc. The Nd +~ and Am +s standards were run in this laboratory in order to check the absolute values of peak wavelengths. The calibration results indicated the instrument to be correct to 1.5 • in the region from 2700 to 4900 A and 2 A from 4900 A to 2/~. The resolving power of the monochromator is about 1.0 ~ in the ultra-violet and vbible ranges and about 3-0 ~ in the near infra-red. The wavelength ~ale b reprodt~ible to 0.5 A. Table I includes corrected wavelength values. The uncertainty in peak locations is --<2A. Slit widths and molar extinction coeff~ients, e. are also given. The Pm+j solution spectrum was compared with solution spectra of Eu* ~, Nd , s Sin" ~, and Am' ~. No trace of the rare-earth ions was ohserved. A trace of Am ~s was detected by a-assay (0.06 mg/ml). ConNquently, the Am ~* peaks at 5033 and 8152 A were subtracted from the promethium spectrum and the remaining peaks taken as Pm+s peaks. The solution absorption spectrum is shown in Fig. 1. Since additional peaks are not obey'veal from 0.8 to i.9 t~. the groundstate multiplets, hi, to ~1~, should be ~.,parated by less than 5400 cm-t The group of peaks around 8000 A are probably due to tmmitions from s14 to the SF and ss multiplets. However, an analysis of the Pro-* spectrum is best undertaken by studying the ion in a solid matrix. Such studies have already begun?~j
Lawrence Radiation Laboratory University of California Berkeley, California
J. B. GRUeEa J.G. CONWAY
is~ j. G. CoNw^v and J. B. Gl~uel~lt,LuminescenceSpectrum of PreCis, UCRL-9042(1960~: J. Chem. Phys. 32, 1586 0960).