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Papers by Teresa Land

Research paper thumbnail of Ab initio study of Al(III) adsorption on stepped {100} surfaces of KDP crystals

Crystals of potassium dihydrogen phosphate (KH 2 PO 4 , KDP) are grown in large scale for use as ... more Crystals of potassium dihydrogen phosphate (KH 2 PO 4 , KDP) are grown in large scale for use as nonlinear material in laser components. Traces of trivalent metal impurities are often added to the supernatant to achieve habit control during crystal growth, selectively inhibiting the growth of the {100} face. Model systems representing AlPO 4 -doped KDP {100} stepped surfaces are prepared and studied using ab initio quantum methods. Results of Hartree-Fock partial optimizations are presented, including estimated energies of ion pair binding to the steps. We find that the PO 4 3ion takes a position not unlike that of a standard phosphate in the crystal lattice, while the aluminum atom is displaced far from a K + ion position to establish coordinations with the PO 4 3ion and to bind with another lattice-bound phosphate. Our optimized structures suggest that it is the formation of a fourth coordination of Al(III) to a third phosphate ion from solution, or perhaps from a nearby position in the lattice, that disrupts further deposition, pinning the steps.

Research paper thumbnail of Investigation of Virus Crystal Growth Mechanisms by In Situ Atomic Force Microscopy

Physical Review Letters, Oct 1, 1995

For the first time, virus crystal growth dynamics and morphology have been investigated in real t... more For the first time, virus crystal growth dynamics and morphology have been investigated in real time on the nanometer scale. Individual monomers on the (111) face of cubic satellite tobacco mosaic virus (STMV) crystals were resolved and used to determine crystal packing. Growth of STMV proceeded by two- and three-dimensional nucleation to formed ``stacks'' of islands. No dislocations were observed. Small islands provided an estimate of critical radius size and the free energy of the step edge, α. Step advancement rates were used to determinate the kinetic coefficient β. Images illustrate mechanisms for defect incorporation and suggest factors that limit growth rate and uniformity.

Research paper thumbnail of In Situ Atomic Force Microscopy Investigation of the {100} Face of KH 2 PO 4 in the Presence of Fe(III), Al(III), and Cr(III)

Langmuir, 2004

Here we report the effects of dissolved metal complexes of Fe(III), Al(III), and Cr(III) on the s... more Here we report the effects of dissolved metal complexes of Fe(III), Al(III), and Cr(III) on the step velocities of the [100] face of KH2PO4 (KDP) as observed with atomic force microscopy. The dependence of step velocity on supersaturation (sigma) exhibits a dead zone that scales with adsorbate concentration. The observed dependence varies with the metal complex. From these data, we derive values for the characteristic adsorption time (tau) for the Al(III) and Cr(III) step-pinning adsorbates as being on the order of several hundred microseconds as compared to 10-100 s for the corresponding Fe(III) step-pinning adsorbates. The values of tau are strikingly different than rates of ligand exchange but are associated with the adsorbate-induced morphology of the surface, including elementary steps that bunch into macrosteps and supersteps. The stoichiometry of the adsorbate species is assumed to be M(HxPO4)x, where M = Fe(III), Al(III), or Cr(III). KDP crystals grown in the presence of the dissolved metals were analyzed using laser ablation inductively coupled plasma mass spectroscopy. The data revealed sectoral zoning on the [100] face, with the concentrations of the incorporated adsorbates in the sector with slower moving elementary steps being 1.7-2.0 times greater than those measured on the sector with fast moving elementary steps.

Research paper thumbnail of The Aspect Ratio of Potassium Dideuterium Phosphate (DKDP) Crystals

Cryst Growth Des, 2005

ABSTRACT

Research paper thumbnail of An In-situ AFM Investigation of Protein Crystallization

In situ atomic force microscopy (AFM) has been used to investigate the crystallization of the sto... more In situ atomic force microscopy (AFM) has been used to investigate the crystallization of the storage protein canavalin during both dislocation controlled step-flow and 2D nucleation controlled multilayer growth at low and high supersaturation, s, respectively. From the dependence of terrace width on s, the critical step length and critical island size we calculate a step edge free energy of 0.8eV. The occurrence of 2D nucleation on large ( 10 μm) terraces and its absence on narrow ( 1μm) terraces and the observation of step homogenization with an exponential time dependence for step-pair decay indicates that the supply of molecules to the steps is via surface diffusion with a barrier to down-step diffusion and a diffusion length of 1μm. Step speeds are found to vary linearly with concentration and give a pH dependent kinetic coefficient for step motion of (0.6 to 3)x10-4 cm/sec. A quantitative analysis of the dependence of step speed on terrace width using the model of Gilmer, Ghez and Cabrera, leads to estimations for the activation energies for adsorption and incorporation of 0.1eV and 0.2eV respectively. Micro-crystal sedimentation and incorporation during growth leads to extreme distortion of the lattice through formation of many stacking faults and micro-grain boundaries. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.

Research paper thumbnail of Growth morphology of vicinal hillocks on the (101) face of KH�PO�: Evidence of surface diffusion

Research paper thumbnail of The secrets of crystal growth

Research paper thumbnail of An empirical electron spectrometer transmission function for applications in quantitative XPS

Surface and Interface Analysis, May 1, 1990

Abstract The use of XPS data for accurate elemental quantitation requires that the transmission f... more Abstract The use of XPS data for accurate elemental quantitation requires that the transmission function of the electron spectrometer be known. Often, the dependence on electron kinetic energy (E k) and spectrometer pass energy (E a) are treated as separable ...

Research paper thumbnail of Sources of optical distortion in rapidly grown crystals of KH�PO�

Research paper thumbnail of The Growth Morphology of the {l_brace}100{r_brace} Surface of KDP (Archerite) on the Molecular Scale

Research paper thumbnail of Characterization of Proton Exchange Layer Profiles in KD2PO4 Crystals by Micro-Raman Spectroscopy

Applied Spectroscopy, Apr 1, 2004

Research paper thumbnail of Effect of Dislocation Cores on Surface Vicinality and Growth Rate of KH2PO4 (101)

Aps March Meeting Abstracts, Mar 1, 1997

We present the results of atomic force microscopy measurements on KDP 101 which show that over th... more We present the results of atomic force microscopy measurements on KDP 101 which show that over the range of supersaturations, 0.03<= s <= 0.3, terrace widths on vicinal growth hillocks formed by dislocations are nearly independent of both supersaturation and dislocation structure, in contradiction to the predictions of simple BCF models. We also show that, for Burgers vectors, b, in excess of one unit step height, the dislocations generate hollow cores with radii whose magnitude and dependence on Burger's vector is in accordance with theoretical predictions. Analytical and numerical results are presented which show that a model that takes into account the effect of these cores on the period of step rotation predicts a dependence of vicinal slope on s and b which is in good agreement with the experimental results. The effect of the core perimeter on the step transit time dominates the effect of reduced step velocity due to stresses near the core. Consequently, a simple analytical expression can be used to describe the slope even when step kinetics are anisotropic. Using these results we explain the reproducible character of the macroscopic growth rate, R, and rescale the data on R(T,s) onto a single curve which follows an Arrhenius relationship. From this data we derive an activation barrier for elementary step motion of 0.3eV. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.

Research paper thumbnail of A Study of Potassium Dihydrogen Phosphate (KDP) Crystal Surfaces by XPS

Surface Science Spectra, 2001

Potassium dihydrogen phosphate KH 2 PO 4 ͑KDP͒ is a transparent dielectric material best known fo... more Potassium dihydrogen phosphate KH 2 PO 4 ͑KDP͒ is a transparent dielectric material best known for its nonlinear optical and electro-optical properties ͑Refs. 1 and 2͒. Because of its nonlinear optical properties, it has been incorporated into various laser systems for harmonic generation and optoelectrical switching. In addition, KDP is particularly suitable for use in large-aperture laser systems such as that located at the National Ignition Facility ͑NIF͒ because it can be grown as a single crystal to large size ͑Refs. 3 and 4͒. Despite the importance of this material, surface composition and surface electronic structure data were found to be nonexistent. X-ray photoemission spectroscopy was thus used to characterize the composition and surface structure of ͑100͒ and ͑101͒ native crystals.

Research paper thumbnail of Mechanisms of growth for protein and virus crystals

Nature structural biology, 1995

The growth of six protein and virus crystals was investigated in situ using atomic force microsco... more The growth of six protein and virus crystals was investigated in situ using atomic force microscopy. Most of the crystals grew principally on steps generated by two-dimensional nucleation on surfaces though some grew by development of spiral dislocations. Apoferritin grew by a rarely encountered mechanism, normal growth, usually associated only with melt or vapour phase crystallization. Cubic crystals of satellite tobacco mosaic virus (STMV) grew, at moderate to high levels of supersaturation, by the direct addition of three-dimensional nuclei followed by their rapid normal growth and lateral expansion, a mechanism not previously described to promote controlled and reproducible crystal growth from solutions. Biological macromolecules apparently utilize a more diverse range of growth mechanisms in their crystallization than any previously studied materials.

Research paper thumbnail of Advanced Crystal Growth Technology

Research paper thumbnail of The Growth Morphology of the {100} Surface of KDP (Archerite) on the Molecular Scale

The Journal of Physical Chemistry B, 2004

ABSTRACT

Research paper thumbnail of Morphological effects induced by the formation of a Pt-adatom lattice gas on Pt(111)

Surface Science, 1992

After sputtering Pt(111)with 600 eV Ar + ions at high sample temperatures three qualitative diffe... more After sputtering Pt(111)with 600 eV Ar + ions at high sample temperatures three qualitative different morphological effects which all occur around 700 K have been identified by scanning tunneling microscopy (STM). The morphological effects observed by STM are: (1) The onset of the layer-by-layer removal, (2) the equilibration of the vacancy island shape and (3) the formation of large vacancy island free zones at the lower terraces in the vicinity of pre-existing steps. The effects are explained by one single assumption: a strong increase of the Pt-adatom density on the Pt(lll) terraces is generated by two-dimensional atom evaporation from step edges at about 700 K.

Research paper thumbnail of Investigation of Virus Crystal Growth Mechanisms by In Situ Atomic Force Microscopy

Physical Review Letters, 1995

Investigation of Virus Crystal Growth Mechanisms by In Situ Atomic Force Microscopy. AJ Malkin 1 ... more Investigation of Virus Crystal Growth Mechanisms by In Situ Atomic Force Microscopy. AJ Malkin 1 , TA Land 2 , Yu. G. Kuznetsov 1 , A. McPherson 1 , and JJ DeYoreo 2 1 Department of Biochemistry, University of California, Riverside ...

Research paper thumbnail of Emergence of Supersteps on KH2PO4 Crystal Surfaces

Physical Review Letters, 2004

In situ AFM investigation of growth on the [100] face of KH2PO4 in the presence of Al(III) and ot... more In situ AFM investigation of growth on the [100] face of KH2PO4 in the presence of Al(III) and other trivalent metals reveals the emergence of a new type of morphological feature-the superstep. Supersteps, or step bunches consisting of 50-1500 elementary steps, are responsible for growth at all supersaturations and exhibit behavior not predicted by accepted models. The step velocity of the superstep is greater than that of single atomic steps and increases with step height. The steepness of the step riser reaches a limiting value of only 11.8 degrees.

Research paper thumbnail of In Situ Atomic Force Microscopy Investigation of the {100} Face of KH 2 PO 4 in the Presence of Fe(III), Al(III), and Cr(III)

Langmuir, 2004

Here we report the effects of dissolved metal complexes of Fe(III), Al(III), and Cr(III) on the s... more Here we report the effects of dissolved metal complexes of Fe(III), Al(III), and Cr(III) on the step velocities of the [100] face of KH2PO4 (KDP) as observed with atomic force microscopy. The dependence of step velocity on supersaturation (sigma) exhibits a dead zone that scales with adsorbate concentration. The observed dependence varies with the metal complex. From these data, we derive values for the characteristic adsorption time (tau) for the Al(III) and Cr(III) step-pinning adsorbates as being on the order of several hundred microseconds as compared to 10-100 s for the corresponding Fe(III) step-pinning adsorbates. The values of tau are strikingly different than rates of ligand exchange but are associated with the adsorbate-induced morphology of the surface, including elementary steps that bunch into macrosteps and supersteps. The stoichiometry of the adsorbate species is assumed to be M(HxPO4)x, where M = Fe(III), Al(III), or Cr(III). KDP crystals grown in the presence of the dissolved metals were analyzed using laser ablation inductively coupled plasma mass spectroscopy. The data revealed sectoral zoning on the [100] face, with the concentrations of the incorporated adsorbates in the sector with slower moving elementary steps being 1.7-2.0 times greater than those measured on the sector with fast moving elementary steps.

Research paper thumbnail of Ab initio study of Al(III) adsorption on stepped {100} surfaces of KDP crystals

Crystals of potassium dihydrogen phosphate (KH 2 PO 4 , KDP) are grown in large scale for use as ... more Crystals of potassium dihydrogen phosphate (KH 2 PO 4 , KDP) are grown in large scale for use as nonlinear material in laser components. Traces of trivalent metal impurities are often added to the supernatant to achieve habit control during crystal growth, selectively inhibiting the growth of the {100} face. Model systems representing AlPO 4 -doped KDP {100} stepped surfaces are prepared and studied using ab initio quantum methods. Results of Hartree-Fock partial optimizations are presented, including estimated energies of ion pair binding to the steps. We find that the PO 4 3ion takes a position not unlike that of a standard phosphate in the crystal lattice, while the aluminum atom is displaced far from a K + ion position to establish coordinations with the PO 4 3ion and to bind with another lattice-bound phosphate. Our optimized structures suggest that it is the formation of a fourth coordination of Al(III) to a third phosphate ion from solution, or perhaps from a nearby position in the lattice, that disrupts further deposition, pinning the steps.

Research paper thumbnail of Investigation of Virus Crystal Growth Mechanisms by In Situ Atomic Force Microscopy

Physical Review Letters, Oct 1, 1995

For the first time, virus crystal growth dynamics and morphology have been investigated in real t... more For the first time, virus crystal growth dynamics and morphology have been investigated in real time on the nanometer scale. Individual monomers on the (111) face of cubic satellite tobacco mosaic virus (STMV) crystals were resolved and used to determine crystal packing. Growth of STMV proceeded by two- and three-dimensional nucleation to formed ``stacks'' of islands. No dislocations were observed. Small islands provided an estimate of critical radius size and the free energy of the step edge, α. Step advancement rates were used to determinate the kinetic coefficient β. Images illustrate mechanisms for defect incorporation and suggest factors that limit growth rate and uniformity.

Research paper thumbnail of In Situ Atomic Force Microscopy Investigation of the {100} Face of KH 2 PO 4 in the Presence of Fe(III), Al(III), and Cr(III)

Langmuir, 2004

Here we report the effects of dissolved metal complexes of Fe(III), Al(III), and Cr(III) on the s... more Here we report the effects of dissolved metal complexes of Fe(III), Al(III), and Cr(III) on the step velocities of the [100] face of KH2PO4 (KDP) as observed with atomic force microscopy. The dependence of step velocity on supersaturation (sigma) exhibits a dead zone that scales with adsorbate concentration. The observed dependence varies with the metal complex. From these data, we derive values for the characteristic adsorption time (tau) for the Al(III) and Cr(III) step-pinning adsorbates as being on the order of several hundred microseconds as compared to 10-100 s for the corresponding Fe(III) step-pinning adsorbates. The values of tau are strikingly different than rates of ligand exchange but are associated with the adsorbate-induced morphology of the surface, including elementary steps that bunch into macrosteps and supersteps. The stoichiometry of the adsorbate species is assumed to be M(HxPO4)x, where M = Fe(III), Al(III), or Cr(III). KDP crystals grown in the presence of the dissolved metals were analyzed using laser ablation inductively coupled plasma mass spectroscopy. The data revealed sectoral zoning on the [100] face, with the concentrations of the incorporated adsorbates in the sector with slower moving elementary steps being 1.7-2.0 times greater than those measured on the sector with fast moving elementary steps.

Research paper thumbnail of The Aspect Ratio of Potassium Dideuterium Phosphate (DKDP) Crystals

Cryst Growth Des, 2005

ABSTRACT

Research paper thumbnail of An In-situ AFM Investigation of Protein Crystallization

In situ atomic force microscopy (AFM) has been used to investigate the crystallization of the sto... more In situ atomic force microscopy (AFM) has been used to investigate the crystallization of the storage protein canavalin during both dislocation controlled step-flow and 2D nucleation controlled multilayer growth at low and high supersaturation, s, respectively. From the dependence of terrace width on s, the critical step length and critical island size we calculate a step edge free energy of 0.8eV. The occurrence of 2D nucleation on large ( 10 μm) terraces and its absence on narrow ( 1μm) terraces and the observation of step homogenization with an exponential time dependence for step-pair decay indicates that the supply of molecules to the steps is via surface diffusion with a barrier to down-step diffusion and a diffusion length of 1μm. Step speeds are found to vary linearly with concentration and give a pH dependent kinetic coefficient for step motion of (0.6 to 3)x10-4 cm/sec. A quantitative analysis of the dependence of step speed on terrace width using the model of Gilmer, Ghez and Cabrera, leads to estimations for the activation energies for adsorption and incorporation of 0.1eV and 0.2eV respectively. Micro-crystal sedimentation and incorporation during growth leads to extreme distortion of the lattice through formation of many stacking faults and micro-grain boundaries. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.

Research paper thumbnail of Growth morphology of vicinal hillocks on the (101) face of KH�PO�: Evidence of surface diffusion

Research paper thumbnail of The secrets of crystal growth

Research paper thumbnail of An empirical electron spectrometer transmission function for applications in quantitative XPS

Surface and Interface Analysis, May 1, 1990

Abstract The use of XPS data for accurate elemental quantitation requires that the transmission f... more Abstract The use of XPS data for accurate elemental quantitation requires that the transmission function of the electron spectrometer be known. Often, the dependence on electron kinetic energy (E k) and spectrometer pass energy (E a) are treated as separable ...

Research paper thumbnail of Sources of optical distortion in rapidly grown crystals of KH�PO�

Research paper thumbnail of The Growth Morphology of the {l_brace}100{r_brace} Surface of KDP (Archerite) on the Molecular Scale

Research paper thumbnail of Characterization of Proton Exchange Layer Profiles in KD2PO4 Crystals by Micro-Raman Spectroscopy

Applied Spectroscopy, Apr 1, 2004

Research paper thumbnail of Effect of Dislocation Cores on Surface Vicinality and Growth Rate of KH2PO4 (101)

Aps March Meeting Abstracts, Mar 1, 1997

We present the results of atomic force microscopy measurements on KDP 101 which show that over th... more We present the results of atomic force microscopy measurements on KDP 101 which show that over the range of supersaturations, 0.03<= s <= 0.3, terrace widths on vicinal growth hillocks formed by dislocations are nearly independent of both supersaturation and dislocation structure, in contradiction to the predictions of simple BCF models. We also show that, for Burgers vectors, b, in excess of one unit step height, the dislocations generate hollow cores with radii whose magnitude and dependence on Burger's vector is in accordance with theoretical predictions. Analytical and numerical results are presented which show that a model that takes into account the effect of these cores on the period of step rotation predicts a dependence of vicinal slope on s and b which is in good agreement with the experimental results. The effect of the core perimeter on the step transit time dominates the effect of reduced step velocity due to stresses near the core. Consequently, a simple analytical expression can be used to describe the slope even when step kinetics are anisotropic. Using these results we explain the reproducible character of the macroscopic growth rate, R, and rescale the data on R(T,s) onto a single curve which follows an Arrhenius relationship. From this data we derive an activation barrier for elementary step motion of 0.3eV. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract No. W-7405-ENG-48.

Research paper thumbnail of A Study of Potassium Dihydrogen Phosphate (KDP) Crystal Surfaces by XPS

Surface Science Spectra, 2001

Potassium dihydrogen phosphate KH 2 PO 4 ͑KDP͒ is a transparent dielectric material best known fo... more Potassium dihydrogen phosphate KH 2 PO 4 ͑KDP͒ is a transparent dielectric material best known for its nonlinear optical and electro-optical properties ͑Refs. 1 and 2͒. Because of its nonlinear optical properties, it has been incorporated into various laser systems for harmonic generation and optoelectrical switching. In addition, KDP is particularly suitable for use in large-aperture laser systems such as that located at the National Ignition Facility ͑NIF͒ because it can be grown as a single crystal to large size ͑Refs. 3 and 4͒. Despite the importance of this material, surface composition and surface electronic structure data were found to be nonexistent. X-ray photoemission spectroscopy was thus used to characterize the composition and surface structure of ͑100͒ and ͑101͒ native crystals.

Research paper thumbnail of Mechanisms of growth for protein and virus crystals

Nature structural biology, 1995

The growth of six protein and virus crystals was investigated in situ using atomic force microsco... more The growth of six protein and virus crystals was investigated in situ using atomic force microscopy. Most of the crystals grew principally on steps generated by two-dimensional nucleation on surfaces though some grew by development of spiral dislocations. Apoferritin grew by a rarely encountered mechanism, normal growth, usually associated only with melt or vapour phase crystallization. Cubic crystals of satellite tobacco mosaic virus (STMV) grew, at moderate to high levels of supersaturation, by the direct addition of three-dimensional nuclei followed by their rapid normal growth and lateral expansion, a mechanism not previously described to promote controlled and reproducible crystal growth from solutions. Biological macromolecules apparently utilize a more diverse range of growth mechanisms in their crystallization than any previously studied materials.

Research paper thumbnail of Advanced Crystal Growth Technology

Research paper thumbnail of The Growth Morphology of the {100} Surface of KDP (Archerite) on the Molecular Scale

The Journal of Physical Chemistry B, 2004

ABSTRACT

Research paper thumbnail of Morphological effects induced by the formation of a Pt-adatom lattice gas on Pt(111)

Surface Science, 1992

After sputtering Pt(111)with 600 eV Ar + ions at high sample temperatures three qualitative diffe... more After sputtering Pt(111)with 600 eV Ar + ions at high sample temperatures three qualitative different morphological effects which all occur around 700 K have been identified by scanning tunneling microscopy (STM). The morphological effects observed by STM are: (1) The onset of the layer-by-layer removal, (2) the equilibration of the vacancy island shape and (3) the formation of large vacancy island free zones at the lower terraces in the vicinity of pre-existing steps. The effects are explained by one single assumption: a strong increase of the Pt-adatom density on the Pt(lll) terraces is generated by two-dimensional atom evaporation from step edges at about 700 K.

Research paper thumbnail of Investigation of Virus Crystal Growth Mechanisms by In Situ Atomic Force Microscopy

Physical Review Letters, 1995

Investigation of Virus Crystal Growth Mechanisms by In Situ Atomic Force Microscopy. AJ Malkin 1 ... more Investigation of Virus Crystal Growth Mechanisms by In Situ Atomic Force Microscopy. AJ Malkin 1 , TA Land 2 , Yu. G. Kuznetsov 1 , A. McPherson 1 , and JJ DeYoreo 2 1 Department of Biochemistry, University of California, Riverside ...

Research paper thumbnail of Emergence of Supersteps on KH2PO4 Crystal Surfaces

Physical Review Letters, 2004

In situ AFM investigation of growth on the [100] face of KH2PO4 in the presence of Al(III) and ot... more In situ AFM investigation of growth on the [100] face of KH2PO4 in the presence of Al(III) and other trivalent metals reveals the emergence of a new type of morphological feature-the superstep. Supersteps, or step bunches consisting of 50-1500 elementary steps, are responsible for growth at all supersaturations and exhibit behavior not predicted by accepted models. The step velocity of the superstep is greater than that of single atomic steps and increases with step height. The steepness of the step riser reaches a limiting value of only 11.8 degrees.

Research paper thumbnail of In Situ Atomic Force Microscopy Investigation of the {100} Face of KH 2 PO 4 in the Presence of Fe(III), Al(III), and Cr(III)

Langmuir, 2004

Here we report the effects of dissolved metal complexes of Fe(III), Al(III), and Cr(III) on the s... more Here we report the effects of dissolved metal complexes of Fe(III), Al(III), and Cr(III) on the step velocities of the [100] face of KH2PO4 (KDP) as observed with atomic force microscopy. The dependence of step velocity on supersaturation (sigma) exhibits a dead zone that scales with adsorbate concentration. The observed dependence varies with the metal complex. From these data, we derive values for the characteristic adsorption time (tau) for the Al(III) and Cr(III) step-pinning adsorbates as being on the order of several hundred microseconds as compared to 10-100 s for the corresponding Fe(III) step-pinning adsorbates. The values of tau are strikingly different than rates of ligand exchange but are associated with the adsorbate-induced morphology of the surface, including elementary steps that bunch into macrosteps and supersteps. The stoichiometry of the adsorbate species is assumed to be M(HxPO4)x, where M = Fe(III), Al(III), or Cr(III). KDP crystals grown in the presence of the dissolved metals were analyzed using laser ablation inductively coupled plasma mass spectroscopy. The data revealed sectoral zoning on the [100] face, with the concentrations of the incorporated adsorbates in the sector with slower moving elementary steps being 1.7-2.0 times greater than those measured on the sector with fast moving elementary steps.