The core-level aluminum excited spectra for lanthanum, the eponymous parent lanthanide metal, are presented together with exemplar spectra highlighting the metals reactivity from reaction with background chamber gases. Recommendations are given for the background integrations limits and form, together with comments on sensitivity factors.

  • Accession #: 01918

  • Technique: XPS and XAES

  • Specimen: La

  • Instrument: Thermo K-Alpha+

  • Major Elements in Spectra: La

  • Minor Elements in Spectra: None

  • Published Spectra: 9

  • Spectral Category: Comparison

The rare earth metal lanthanum (La) is the eponymic element of the lanthanide series. Although typically considered the first of the f-block elements (Ref. 1), La does not have any f-electrons and exhibits a ground state electronic configuration of [Xe] 5d1 6s2.

To date, there have been a number of papers published in Surface Science Spectra (SSS) of La based compounds, such as those in Refs. 2–5. While the spectra of La has been previously published in SSS as part of a series of the third-row transition metals (Ref. 6), the spectra presented herein are different for several reasons. First, these are part of a self-consistent series of spectra for the lanthanide series of elements—see, for example, Ref. 7. Second, some spectra are presented over a larger energy window than previously reported, highlighting more structure, and finally, representative spectra from the reaction of the La metal with the background chamber gases are also shown.

Much like its elemental family, La has an affinity for hydrogen, oxygen, water, and halides, hence maintaining a clean surface for analysis is difficult. Within this reference, the spectra for clean La are presented, which were obtained by light argon sputtering (30 s) between acquisitions.

To illustrate the oxidation through adsorption of background gases, Fig. 1 shows the La 3d and O 1s core-level spectra for different times during a cycle of constant analysis of the core levels. The formation of the lanthanum oxide phase in the La 3d spectra is quite evident following ca. 200 min, and this is concomitant with the development of a second peak in the O 1s spectrum which we do not ascribe to a purely hydroxyl state. Analysis of the valence band (not shown) for this data set, reveals little intensity close to that expected for the O 2pσ bonds which would be due to OH species as discussed in Ref. 8. While the presence of small concentrations of hydroxyl groups are not discounted, this peak is assigned as in Ref. 8, to the oxygen atoms in two distinct environments, with the shift in binding energy a consequence of both initial and final state effects and discussed in Ref. 8.

FIG. 1.

La 3d and O 1s core levels spectra after approximately 0, 30, 60, 100, 200, and 250 min of data acquisition.

FIG. 1.

La 3d and O 1s core levels spectra after approximately 0, 30, 60, 100, 200, and 250 min of data acquisition.

Close modal

Specimen: Lanthanum, La

CAS Registry #: 7439-91-0

Specimen Characteristics: Homogeneous; solid; polycrystalline; conductor; metal; and other

Chemical Name: Lanthanum

Source: Thermo Scientific

Composition: La

Form: Solid, approximately 20 × 50 mm2

Structure: La

History and Significance: Metallic pieces, 99.9% grade material obtained from Thermo Scientific in mineral oil

As Received Condition: Received as silvery-black, tarnished metallic pieces stored in a mineral oil

Analyzed Region: Elliptical region within the approximate center of the sputtered area.

Ex Situ Preparation/Mounting: A suitably sized fragment was removed from the mineral oil and polished in the surface oil residue, using SiC paper (grit size 7), to form a visually flat and smooth surface. The sample was subsequently washed in iso-propyl alcohol and further polished with iso-propyl alcohol and SiC paper. The sample was rinsed, dried via solvent evaporation, and attached to a conducting sample plate using copper clips.

In Situ Preparation: Argon ion sputtering

Charge Control: None

Temp. During Analysis: 298 K

Pressure During Analysis: 2.8 × 10−7 Pa

Preanalysis Beam Exposure: 20 s

Manufacturer and Model: Thermo Fisher Scientific K-Alpha+

Analyzer Type: Spherical sector

Detector: Multichannel resistive plate

Number of Detector Elements: 128

Analyzer Mode: Constant pass energy

Throughput (T = EN): Calculated from a polynomial fit to a plot of log[peak area/(PE*XSF)] versus log(KE/PE), where PE is the pass energy, KE is the kinetic energy, and XSF is the relative sensitivity factor.9 

Excitation Source Window: No window

Excitation Source: Al Kα monochromatic

Source Energy: 1486.6 eV

Source Strength: 72 W

Source Beam Size: 600 × 400 μm2

Signal Mode: Multichannel direct

Incident Angle: 60°

Source-to-Analyzer Angle: 60°

Emission Angle:

Specimen Azimuthal Angle:

Acceptance Angle from Analyzer Axis:

Analyzer Angular Acceptance Width: 30° × 30°

Manufacturer and Model: Thermo Scientific MAGCIS

Energy: 4000 eV

Current: 6 mA

Current Measurement Method: Faraday cup

Sputtering Species and Charge: Ar+

Spot Size (unrastered): 50 μm

Raster Size: 2000 × 1000 μm2

Incident Angle: 58°

Polar Angle: 58°

Azimuthal Angle: 90°

Comment: The ion gun was used to clean the as-introduced sample for 300 s and then for 30 s between each region to minimize any adsorption of background gases which readily oxidize the material during analysis. No annealing was performed.

Energy Scale Correction: The sample is conductive and mounted in direct contact with the metallic sample holder, hence no calibration is required.

Recommended Energy Scale Shift: 0

Peak Shape and Background Method: Due to the complexity of some of the photoemission peaks and background intensity (e.g., La 3d, primarily due to the overlap with La MNN Auger features), the use of a two parameter Tougaard background (U2 Tougaard background in CasaXPS) has been employed. Recommended background start and end points (±0.5 eV) are given below, together with a suggested “C” parameter for the U2 background in CasaXPS given in parentheses:

La 4p: 185–220 eV (−650)

La 4d: 94–122 eV (−150, else use Shirley)

La 3d5/2: 827–847 eV (−650)

La 3d—complete doublet: 827–863 eV (−350)

Quantitation Method: Data analysis was performed using CasaXPS performed in CasaXPS V2.3.26 rev1.2Y, using a U2 Tougaard background unless otherwise specified. Electron escape depth correction was performed using the TPP-2M equation within CasaXPS and peak areas corrected using Scofield sensitivity factors. A modified sensitivity factor is used for the La 4p level as noted in the comments on the spectral features table.

SPECTRAL FEATURES TABLE

Spectrum ID #Element/TransitionPeak Energy (eV)Peak Width FWHM (eV)Peak Area (eV × counts/s)Sensitivity FactorConcentration (at. %)Peak Assignment
01918-01 La 3d 836.0 … 44 504 074 47.62 100 La 3d—Energy for 5/2 peak 
01918-02 Valence … … … … … Fermi level, La 5p, La 5s 
01918-02 La 5p3/2 16.7 … … … … … 
01918-02 La 5p1/2 19.2 … … … … … 
01918-02 La 5s 34.3 … … … … … 
01918-03a La 4d5/2 102.6 … 937 860 6.52 … La 4d doublet 
01918-03a La 4d3/2 105.6 … … … … … 
01918-04b La 4p3/2 196.2 … 393 065 2.8 … La 4p3/2 
01918-04b La 4p1/2 … … … … … See comments 
01918-05 La 4s 274.8 … … … … … 
01918-06c La MNN 758.3 … … … … La MNN Auger structure 
01918-07 La 3d5/2 835.8 1.8 3 991 907 28.12 … La 3d5/2 
01918-07 La 3d3/2 852.6 1.8 … 19.50 … La 3d3/2 
01918-08d La 3p3/2 1126.7 5.7 1 246 836 12.11 … La 3p3/2 
01918-09d La 3p1/2 1027.5 5.3 563 951 5.55 … La 3p1/2 
Spectrum ID #Element/TransitionPeak Energy (eV)Peak Width FWHM (eV)Peak Area (eV × counts/s)Sensitivity FactorConcentration (at. %)Peak Assignment
01918-01 La 3d 836.0 … 44 504 074 47.62 100 La 3d—Energy for 5/2 peak 
01918-02 Valence … … … … … Fermi level, La 5p, La 5s 
01918-02 La 5p3/2 16.7 … … … … … 
01918-02 La 5p1/2 19.2 … … … … … 
01918-02 La 5s 34.3 … … … … … 
01918-03a La 4d5/2 102.6 … 937 860 6.52 … La 4d doublet 
01918-03a La 4d3/2 105.6 … … … … … 
01918-04b La 4p3/2 196.2 … 393 065 2.8 … La 4p3/2 
01918-04b La 4p1/2 … … … … … See comments 
01918-05 La 4s 274.8 … … … … … 
01918-06c La MNN 758.3 … … … … La MNN Auger structure 
01918-07 La 3d5/2 835.8 1.8 3 991 907 28.12 … La 3d5/2 
01918-07 La 3d3/2 852.6 1.8 … 19.50 … La 3d3/2 
01918-08d La 3p3/2 1126.7 5.7 1 246 836 12.11 … La 3p3/2 
01918-09d La 3p1/2 1027.5 5.3 563 951 5.55 … La 3p1/2 
a

Sensitivity factor is for the whole spin–orbit split peak and associated structure over the limits defined earlier.

b

Sensitivity factor is modified from that of Scofield (4.33) to 2.8. Note this is almost equal to the sensitivity factor value for the 4p3/2 peak, which may indicate errors in assignment due to the multiplet splitting of the La 4p peak. Use of the full Scofield value necessitates the inclusion of structure up to ca. 250 eV.

Note the value for the 4p1/2 peak taken from the Lawrence Berkeley National Laboratory X-Ray Data Handbook (https://xdb.lbl.gov/) is 206.0 eV and given the identical reported 4p3/2 binding energies in this paper and the handbook the value is presented here for completeness. It is noted the value is different from that reported in Ref. 6, however, given complex structure in this spectral region and broadening of the 4p1/2 state in lanthanides by super Coster–Kroning effects, a distinct peak is not visible.

c

Energy given as binding energy as plotted. Equivalent kinetic energy is 728.3 eV. This is the value for the sharpest Auger peak.

d

Position and FWHM obtained by peak fit using an asymmetric function, LA(0.7,1.2,243) in CasaXPS, with a LA(50) peak for the remaining structure. It is not recommended to use these peaks for quantification, at least not over the presented ranges, as they do not afford a similar elemental ratio to the other orbitals.

ANALYZER CALIBRATION TABLE

Spectrum ID #Element/TransitionPeak Energy (eV)Peak Width FWHM (eV)Peak Area (eV × counts/s)Sensitivity FactorConcentration (at. %)Peak Assignment
… Au 4f7/2 83.99 0.78 1 252 439 9.58 100 Gold metal 
… Ag 3d5/2 368.28 0.61 1 676 008 7.38 100 Silver metal 
… Cu 2p3/2 932.67 0.86 2 867 973 16.73 100 Copper metal 
Spectrum ID #Element/TransitionPeak Energy (eV)Peak Width FWHM (eV)Peak Area (eV × counts/s)Sensitivity FactorConcentration (at. %)Peak Assignment
… Au 4f7/2 83.99 0.78 1 252 439 9.58 100 Gold metal 
… Ag 3d5/2 368.28 0.61 1 676 008 7.38 100 Silver metal 
… Cu 2p3/2 932.67 0.86 2 867 973 16.73 100 Copper metal 

GUIDE TO FIGURES

Spectrum (Accession) #Spectral RegionVoltage ShiftMultiplierBaselineComment #
01918-01 Survey … 
01918-02 La 5s, La 5p, Valence 0.2 eV step size 
01918-03 La 4d … 
01918-04 La 4p … 
01918-05 La 4s … 
01918-06 La MNN … 
01918-07 La 3d … 
01918-08 La 3p3/2 … 
01918-09 La 3p1/2 … 
Spectrum (Accession) #Spectral RegionVoltage ShiftMultiplierBaselineComment #
01918-01 Survey … 
01918-02 La 5s, La 5p, Valence 0.2 eV step size 
01918-03 La 4d … 
01918-04 La 4p … 
01918-05 La 4s … 
01918-06 La MNN … 
01918-07 La 3d … 
01918-08 La 3p3/2 … 
01918-09 La 3p1/2 … 

Accession #:01918-01
■ Specimen: La 
■ Technique: XPS 
■ Spectral Region: Survey 
Instrument: Thermo Fisher Scientific K-Alpha+ 
Excitation Source: Al Kα monochromatic 
Source Energy: 1486.6 eV 
Source Strength: 72 W 
Source Size: 0.6 × 0.4 mm2 
Analyzer Type: Spherical sector analyzer 
Incident Angle: 60° 
Emission Angle: 0° 
Analyzer Pass Energy: 200 eV 
Analyzer Resolution: 1.5 eV 
Total Signal Accumulation Time: 29 s 
Total Elapsed Time: 29 s 
Number of Scans: 
Effective Detector Width: 27.1 eV 
Accession #:01918-01
■ Specimen: La 
■ Technique: XPS 
■ Spectral Region: Survey 
Instrument: Thermo Fisher Scientific K-Alpha+ 
Excitation Source: Al Kα monochromatic 
Source Energy: 1486.6 eV 
Source Strength: 72 W 
Source Size: 0.6 × 0.4 mm2 
Analyzer Type: Spherical sector analyzer 
Incident Angle: 60° 
Emission Angle: 0° 
Analyzer Pass Energy: 200 eV 
Analyzer Resolution: 1.5 eV 
Total Signal Accumulation Time: 29 s 
Total Elapsed Time: 29 s 
Number of Scans: 
Effective Detector Width: 27.1 eV 

Accession #:01918-01
■ Specimen: La 
■ Technique: XPS 
■ Spectral Region: Survey 
Instrument: Thermo Fisher Scientific K-Alpha+ 
Excitation Source: Al Kα monochromatic 
Source Energy: 1486.6 eV 
Source Strength: 72 W 
Source Size: 0.6 × 0.4 mm2 
Analyzer Type: Spherical sector analyzer 
Incident Angle: 60° 
Emission Angle: 0° 
Analyzer Pass Energy: 200 eV 
Analyzer Resolution: 1.5 eV 
Total Signal Accumulation Time: 29 s 
Total Elapsed Time: 29 s 
Number of Scans: 
Effective Detector Width: 27.1 eV 
Accession #:01918-01
■ Specimen: La 
■ Technique: XPS 
■ Spectral Region: Survey 
Instrument: Thermo Fisher Scientific K-Alpha+ 
Excitation Source: Al Kα monochromatic 
Source Energy: 1486.6 eV 
Source Strength: 72 W 
Source Size: 0.6 × 0.4 mm2 
Analyzer Type: Spherical sector analyzer 
Incident Angle: 60° 
Emission Angle: 0° 
Analyzer Pass Energy: 200 eV 
Analyzer Resolution: 1.5 eV 
Total Signal Accumulation Time: 29 s 
Total Elapsed Time: 29 s 
Number of Scans: 
Effective Detector Width: 27.1 eV 

Close modal

  • Accession #:01918-02

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 5s, La 5p, Valence

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy 50 eV

  • Analyzer Resolution: 0.2 eV

  • Total Signal Accumulation Time: 111 s

  • Total Elapsed Time: 170 s

  • Number of Scans: 10

  • Effective Detector Width: 6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

  • Accession #:01918-02

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 5s, La 5p, Valence

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy 50 eV

  • Analyzer Resolution: 0.2 eV

  • Total Signal Accumulation Time: 111 s

  • Total Elapsed Time: 170 s

  • Number of Scans: 10

  • Effective Detector Width: 6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

Close modal

  • Accession #:01918-03

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 4d

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 72 s

  • Total Elapsed Time: 272 s

  • Number of Scans: 4

  • Effective Detector Width:6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

  • Accession #:01918-03

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 4d

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 72 s

  • Total Elapsed Time: 272 s

  • Number of Scans: 4

  • Effective Detector Width:6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

Close modal

  • Accession #:01918-04

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 4p

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 79 s

  • Total Elapsed Time: 381 s

  • Number of Scans: 4

  • Effective Detector Width: 6.8 eV

  • Comments: See comments on the Spectral Features Table section. Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

  • Accession #:01918-04

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 4p

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 79 s

  • Total Elapsed Time: 381 s

  • Number of Scans: 4

  • Effective Detector Width: 6.8 eV

  • Comments: See comments on the Spectral Features Table section. Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

Close modal

  • Accession #:01918-05

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 4s

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 79 s

  • Total Elapsed Time: 490 s

  • Number of Scans: 4

  • Effective Detector Width: 6.8 eV

  • Comments: Loss structure of 4 s peak overlaps C1s region. Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

  • Accession #:01918-05

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 4s

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 79 s

  • Total Elapsed Time: 490 s

  • Number of Scans: 4

  • Effective Detector Width: 6.8 eV

  • Comments: Loss structure of 4 s peak overlaps C1s region. Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

Close modal

  • Accession #:01918-06

  • Specimen: La

  • Technique: XAES

  • Spectral Region: La MNN

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 90 s

  • Total Elapsed Time: 610 s

  • Number of Scans: 10

  • Effective Detector Width: 6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

  • Accession #:01918-06

  • Specimen: La

  • Technique: XAES

  • Spectral Region: La MNN

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 90 s

  • Total Elapsed Time: 610 s

  • Number of Scans: 10

  • Effective Detector Width: 6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

Close modal

  • Accession #:01918-07

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 3d

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size: 0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 79 s

  • Total Elapsed Time: 719 s

  • Number of Scans: 4

  • Effective Detector Width: 6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time. Background subtraction is complicated by overlap of La MNN Auger features, see comments in the Data Analysis section.

  • Accession #:01918-07

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 3d

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size: 0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 79 s

  • Total Elapsed Time: 719 s

  • Number of Scans: 4

  • Effective Detector Width: 6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time. Background subtraction is complicated by overlap of La MNN Auger features, see comments in the Data Analysis section.

Close modal

  • Accession #:01918-08

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 3p3/2

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size: 0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 76 s

  • Total Elapsed Time: 825 s

  • Number of Scans: 6

  • Effective Detector Width: 6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

  • Accession #:01918-08

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 3p3/2

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size: 0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 76 s

  • Total Elapsed Time: 825 s

  • Number of Scans: 6

  • Effective Detector Width: 6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time.

Close modal

  • Accession #:01918-09

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 3p1/2

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 76 s

  • Total Elapsed Time: 959 s

  • Number of Scans: 6

  • Effective Detector Width: 6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time

  • Accession #:01918-09

  • Specimen: La

  • Technique: XPS

  • Spectral Region: La 3p1/2

  • Instrument: Thermo Fisher Scientific K-Alpha+

  • Excitation Source: Al Kα monochromatic

  • Source Energy: 1486.6 eV

  • Source Strength: 72 W

  • Source Size:0.6 × 0.4 mm2

  • Analyzer Type: Spherical sector

  • Incident Angle: 60°

  • Emission Angle: 0°

  • Analyzer Pass Energy: 50 eV

  • Analyzer Resolution: 0.1 eV

  • Total Signal Accumulation Time: 76 s

  • Total Elapsed Time: 959 s

  • Number of Scans: 6

  • Effective Detector Width: 6.8 eV

  • Comments: Spectra were collected after a 30 s sputter after collection of the prior spectrum to minimize any oxidation. Total elapsed time includes previous scans and sputtering time

Close modal

This work was performed through the support of the EPSRC National Facility for x-ray photoelectron spectroscopy (‘HarwellXPS’, Nos. EP/Y023587/1, EP/Y023609/1, EP/Y023536/1, EP/Y023552/1, and EP/Y023544/1).

The author has no conflicts to disclose.

David J. Morgan: Conceptualization (equal); Data curation (equal); Formal analysis (equal); Investigation (equal); Methodology (equal); Project administration (equal); Resources (equal); Validation (equal); Writing – original draft (equal); Writing – review & editing (equal).

The data that support the findings of this study are available within the article and its supplementary material.

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Published open access through an agreement withJISC Collections

Supplementary Material