Publications

@article{angel_uncertainties_2025,

title = {Uncertainties of recalculated bond lengths, angles and polyhedral volumes as implemented in the textitCrystal Palace program for parametric crystal structure analysis},

author = {Ross J. Angel and Mattia L. Mazzucchelli and Lisa Baratelli and Catherine F. Schweinle and Tonci Balić-Žunić and Javier Gonzalez-Platas and Matteo Alvaro},

url = {https://journals.iucr.org/paper?S2053273325002682},

doi = {10.1107/S2053273325002682},

issn = {2053-2733},

year  = {2025},

date = {2025-05-01},

urldate = {2025-05-01},

journal = {Acta Crystallographica Section A Foundations and Advances},

volume = {81},

number = {3},

pages = {202–210},

abstract = {Crystal Palace 

 is a new Windows program for Parametric Analysis of Least-squares and Atomic Coordination with Estimated standard uncertainties (e.s.u.'s). The primary purpose of the program is to organize the refined structures from parametric structural studies (as a function of pressure or temperature or a series of compositions) for analysis of the structural trends, and the production of tables for publication without the risks associated with manual editing. The program reads structural information from one or more crystallographic information format (cif) files. It organizes the data by finding the structurally equivalent atoms in each structure and therefore can correctly organize structural information even if atom names or site occupancies are different, or the atom lists in the cif files are ordered differently. A major shortcoming of cif files as currently used is that they do not contain the full variance–covariance matrix from the structure refinement, but only the uncertainties of the individual positional parameters. Without the covariance of positional parameters, the e.s.u.'s of bond lengths and angles cannot be determined. 

 Crystal Palace 

 uses symmetry to estimate the major contributions to the covariance of atomic coordinates and thus realistic uncertainties of bond lengths, angles and polyhedral volumes. 

 Crystal Palace 

 also calculates various polyhedral distortion parameters and rigid-body corrections to bond lengths.},

keywords = {Crystallography, Single-crystal X-ray diffraction, software development},

pubstate = {published},

tppubtype = {article}

}

@article{murri_role_2022,

title = {The role of symmetry-breaking strains on quartz inclusions in anisotropic hosts: Implications for Raman elastic geobarometry},

author = {M. Murri and J. P. Gonzalez and M. L. Mazzucchelli and M. Prencipe and B. Mihailova and R. J. Angel and M. Alvaro},

url = {https://www.sciencedirect.com/science/article/pii/S0024493722001256},

doi = {10.1016/j.lithos.2022.106716},

issn = {0024-4937},

year  = {2022},

date = {2022-08-01},

urldate = {2022-08-01},

journal = {Lithos},

volume = {422-423},

pages = {106716},

abstract = {Raman elastic geobarometry for mineral host-inclusion systems is used to determine the strains acting on an inclusion still entrapped in its host by measuring its Raman wavenumber shifts which are interpreted through the phonon-mode Grüneisen tensors of the inclusion phase. The calculated inclusion strains can then be used in an elastic model to calculate the pressure and temperature conditions of entrapment. This method is applied frequently to host inclusion systems where the host is almost elastically isotropic (e.g. garnet) and the inclusion is elastically anisotropic (e.g. quartz and zircon). In this case, when the entrapment occurs under hydrostatic conditions the host will impose isotropic strains on the inclusion which in turn will develop non-hydrostatic stress. In this scenario the symmetry of the inclusion mineral is preserved and the strains in the inclusion can be measured via Raman spectroscopy using the phonon-mode Grüneisen tensor approach. However, a more complex situation arises when the host-inclusion system is fully anisotropic, such as when a quartz inclusion is entrapped within a zircon host, because the symmetry of the inclusion can be broken due to the external anisotropic strain field imposed on the inclusion by the host, which in turn will modify the phonon modes. We therefore calculated the strain states of quartz inclusions entrapped in zircon hosts in multiple orientations and at various geologically relevant pressure and temperature conditions. We then performed ab initio Hartree-Fock/Density Functional Theory (HF/DFT) simulations on α-quartz in these strain states. These HF/DFT simulations show that the changes in the positions of the Raman modes produced by strains that are expected for symmetry broken quartz inclusions in zircon are generally similar to those that would be seen if the quartz inclusions remained truly trigonal in symmetry. Therefore, the use of the trigonal phonon-mode Grüneisen tensor to determine the inclusion strains does not lead to geologically significant errors in calculated quartz inclusion entrapment pressures in zircon.},

keywords = {ab-initio, Crystallography, Density Functional Theory, DFT, Elastic anisotropy, Elastic thermobarometry, Raman spectroscopy, Raman thermobarometry},

pubstate = {published},

tppubtype = {article}

}

@article{angel_garnet_2022,

title = {Garnet EoS: a critical review and synthesis},

author = {Ross J. Angel and Mattia Gilio and Mattia Mazzucchelli and Matteo Alvaro},

url = {https://doi.org/10.1007/s00410-022-01918-5},

doi = {10.1007/s00410-022-01918-5},

issn = {1432-0967},

year  = {2022},

date = {2022-05-01},

urldate = {2022-05-01},

journal = {Contributions to Mineralogy and Petrology},

volume = {177},

number = {5},

pages = {54},

abstract = {All available volume and elasticity data for the garnet end-members grossular, pyrope, almandine and spessartine have been re-evaluated for both internal consistency and for consistency with experimentally measured heat capacities. The consistent data were then used to determine the parameters of third-order Birch–Murnaghan EoS to describe the isothermal compression at 298 K and a Mie–Grüneisen–Debye thermal-pressure EoS to describe the PVT behaviour. In a full Mie–Grüneisen–Debye EoS, the variation of the thermal Grüneisen parameter with volume is defined as $$textbackslashgamma = textbackslashgamma _0textbackslashleft(textbackslashfracVV_0textbackslashright)textasciicircumq$$. For grossular and pyrope garnets, there is sufficient data to refine q which has a value of q = 0.8(2) for both garnets. For other garnets, the data do not constrain the value of q and we therefore refined a q-compromise version of the Mie–Grüneisen–Debye EoS in which both γ/V and the Debye temperature θ D are held constant at all P and T, leading to $$textbackslashleft( textbackslashraise0.7extextbackslashhbox$textbackslashpartial C_textbackslashtextV $ textbackslash!textbackslashmathordtextbackslashleft/ textbackslashvphantom textbackslashpartial C_textbackslashtextV  textbackslashpartial Ptextbackslashright.textbackslashkern-textbackslashnulldelimiterspace textbackslash!textbackslashlower0.7extextbackslashhbox$textbackslashpartial P$ textbackslashright)_textbackslashtextT = 0$$, parallel isochors and constant isothermal bulk modulus along an isochor. Final refined parameters for the q-compromise Mie–Grüneisen–Debye EoS are: PyropeAlmandineSpessartineGrossularV0 (cm3/mol)a113.13115.25117.92125.35K0T (GPa)169.3 (3)174.6 (4)177.57 (6)167.0 (2)$$Ktextasciicircumtextbackslashprime_0textbackslashtextT$$4.55 (5)5.41 (13)4.6 (3)5.07 (8)θ D0771 (28)862 (22)860 (35)750 (13)γ01.185 (12)1.16 (fixed)1.18 (3)1.156 (6)for pyrope and grossular, the two versions of the Mie–Grüneisen–Debye EoS predict indistinguishable properties over the metamorphic pressure and temperature range, and the same properties as the EoS based on experimental heat capacities. The biggest change from previously published EoS is for almandine for which the new EoS predicts geologically reasonable entrapment conditions for zircon inclusions in almandine-rich garnets.},

keywords = {Crystallography, Elastic thermobarometry, Elasticity, Garnet, Single-crystal X-ray diffraction, thermodynamics},

pubstate = {published},

tppubtype = {article}

}

@article{angel_self-consistent_2021,

title = {A self-consistent approach to describe unit-cell-parameter and volume variations with pressure and temperature},

author = {R. Angel and M. Mazzucchelli and J. Gonzalez-Platas and M. Alvaro},

doi = {10.1107/S1600576721009092},

issn = {1600-5767},

year  = {2021},

date = {2021-12-01},

urldate = {2021-12-01},

journal = {Journal of Applied Crystallography},

volume = {54},

number = {6},

pages = {1621--1630},

abstract = {A method is presented for the self-consistent description of the variations of unit-cell parameters of crystals with pressure and temperature.},

keywords = {Crystallography, Elastic anisotropy, Elastic thermobarometry, Elasticity, thermodynamics},

pubstate = {published},

tppubtype = {article}

}

@article{Campomenosi2020,

title = {Using polarized Raman spectroscopy to study the stress gradient in mineral systems with anomalous birefringence},

author = {N. Campomenosi and Mattia Luca Mazzucchelli and B. D. Mihailova and Ross John Angel and Matteo Alvaro},

url = {https://doi.org/10.1007/s00410-019-1651-x},

doi = {10.1007/s00410-019-1651-x},

issn = {14320967},

year  = {2020},

date = {2020-02-01},

urldate = {2020-02-01},

journal = {Contributions to Mineralogy and Petrology},

volume = {175},

number = {2},

pages = {1--16},

abstract = {Polarized Raman spectroscopy was applied to garnet hosts which exhibit anomalous birefringence around inclusions of zircon and quartz to elucidate the spatial distribution of the anisotropic strain fields in the vicinity of the host-inclusion boundary. We show that there is a direct relationship between the stress-induced birefringence and the Raman scattering generated by the fully symmetric phonon modes (the A1g modes in cubic crystals). Our experimental results coupled with selected finite element models show that the ratio between the measured Raman peak intensity collected in cross and parallel polarized scattering geometries of totally symmetric modes represents a useful tool to constrain the radial stress profile in the host around the inclusions. Further, we demonstrate how group-theoretical considerations and tensor analysis of the morphic effect (external-field-induced change of the symmetry) on the phonons and the optical properties of the host can help to derive useful information on the symmetry of the stress field. Finally, we show experimentally that, under the same amount of applied stress, this approach is more sensitive than the commonly used approach of measuring differences in phonon frequencies and provides better opportunities to map the spatial variations of strain. This approach is an alternative technique to study structural phenomena associated with anomalous birefringence in host crystals surrounding stressed inclusions and could be applied to other systems in which similar optical effects are observed.},

keywords = {Crystallography, Elastic anisotropy, Elasticity, Raman spectroscopy, Stress},

pubstate = {published},

tppubtype = {article}

}

@article{Scandolo2015ab,

title = {Thermal expansion behaviour of orthopyroxenes: the role of the Fe-Mn substitution},

author = {L. Scandolo and Mattia Luca Mazzucchelli and M. Alvaro and Fabrizio Nestola and F. Pandolfo and M. C. C Domeneghetti},

url = {https://doi.org/10.1180/minmag.2015.079.1.07},

doi = {10.1180/minmag.2015.079.1.07},

issn = {14718022},

year  = {2015},

date = {2015-01-01},

urldate = {2015-01-01},

journal = {Mineralogical Magazine},

volume = {79},

number = {1},

pages = {71--87},

keywords = {Crystallography, Elasticity, equations of state, Single-crystal X-ray diffraction, thermal expansion, thermodynamics},

pubstate = {published},

tppubtype = {article}

}

@article{Milani2015,

title = {Diamond–garnet geobarometry: The role of garnet compressibility and expansivity},

author = {Sula Milani and Fabrizio Nestola and Matteo Alvaro and Daria Pasqual and Mattia Luca Mazzucchelli and M C Domeneghetti and C A Geiger},

url = {http://www.sciencedirect.com/science/article/pii/S0024493715001097},

doi = {10.1016/j.lithos.2015.03.017},

year  = {2015},

date = {2015-01-01},

urldate = {2015-01-01},

journal = {Lithos},

volume = {227},

number = {0},

pages = {140--147},

keywords = {Crystallography, Diamond, Elastic thermobarometry, equations of state, Experiments, Garnet, petrology, Raman thermobarometry, Single-crystal X-ray diffraction, thermal expansion, thermodynamics},

pubstate = {published},

tppubtype = {article}

}

@article{Alvaro2015,

title = {A new micro-furnace for in situ high-temperature single-crystal X-ray diffraction measurements},

author = {M. Alvaro and Ross John Angel and C. Marciano and S. Milani and L. Scandolo and Mattia Luca Mazzucchelli and G. Zaffiro and G. Rustioni and M. Briccola and M. C. Domeneghetti and F. Nestola},

url = {http://scripts.iucr.org/cgi-bin/paper?S1600576715011371},

doi = {10.1107/s1600576715011371},

issn = {1600-5767},

year  = {2015},

date = {2015-01-01},

urldate = {2015-01-01},

journal = {Journal of Applied Crystallography},

volume = {48},

number = {4},

pages = {1192--1200},

abstract = {A new micro-furnace equipped with an H-shaped resistance heater has been developed to conduct in situ single-crystal X-ray diffraction experiments at high temperature. The compact design of the furnace does not restrict access to reciprocal space out to 2θ = 60°. Therefore, unit-cell parameters and intensity data can be determined to a resolution of 0.71 Å with Mo radiation. The combined use of mineral phases with well characterized lattice expansion ( e.g. pure Si and SiO 2 quartz) and a small-diameter (0.025 mm) K-type thermocouple allowed accurate temperature calibration from room temperature to about 1273 K and consequent evaluation of thermal gradients and stability. The new furnace design allows temperatures up to about 1273 K to be reached with a thermal stability better than ±5 K even at the highest temperatures. Measurements of the lattice thermal expansion of pure silicon (Si), pure synthetic grossular garnet (Ca 3 Al 2 Si 3 O 12 ) and quartz (SiO 2 ) are presented to demonstrate the performance of the device. Its main advantages and limitations and important considerations for using it to perform high-temperature diffraction measurements are discussed.},

keywords = {Crystallography, Experiments, Single-crystal X-ray diffraction, thermal expansion},

pubstate = {published},

tppubtype = {article}

}