• AC electrokinetic induced non-Newtonian electrothermal blood flow in 3D microfluidic biosensor with ring electrodes for point-of-care diagnostics

      Ren, Qinlong; Wang, Yichao; Lin, Xixiang; Chan, Cho Lik; Univ Arizona, Dept Aerosp & Mech Engn (AMER INST PHYSICS, 2019-08-23)
      Efficient pumping of whole blood is an essential task in biomedical engineering, especially for point-of-care diagnostics using lab-on-a-chip devices. Alternating current (AC) electrokinetics have been widely used for several different applications among which pumping fluids using the precisely controlled electric field without any moving mechanical parts is significant. Due to its high conductive characteristic, it is difficult to drive the blood flow using the AC electroosmosis phenomenon because the electric double layer is highly compressed. Fortunately, the AC electrothermal (ACET) phenomenon occurs due to the variation of temperature-dependent permittivity and conductivity caused by Joule heating effects or other heat sources making it powerful for driving high electrical conductivity physiological fluids in biomedical devices. Compared with Newtonian fluids like saline solutions or urine, the non-Newtonian rheological nature and AC frequency-dependent dielectric property of blood make its ACET driving mechanism more complicated and attractive. In this paper, ACET induced blood flow in the 3D microfluidic channel is modeled by the lattice Boltzmann method accelerated using graphics processor units. The Carreau-Yasuda model is applied to simulate the shear-thinning behavior of blood flow, and its electrothermal pumping efficiency is investigated with respect to the AC electrode configuration, AC voltage magnitude, and AC signal frequency by comparing it with the ACET pumping of Newtonian fluids using scaling law analysis. The results demonstrate that the ACET phenomenon is effective for pumping non-Newtonian whole blood flow in microfluidic devices with ring electrodes which will contribute to the point-of-care diagnostic of bacterial bloodstream infections or rapid detection of circulating tumor cells. Published under license by AIP Publishing.
    • Algorithms for calculating mass-velocity and Darwin relativistic corrections with n-electron explicitly correlated Gaussians with shifted centers

      Stanke, Monika; Palikot, Ewa; Adamowicz, Ludwik; Univ Arizona, Dept Chem & Biochem; Univ Arizona, Dept Phys; Institute of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University, ul. Grudzia̧dzka 5, Toruń, PL 87-100, Poland; Institute of Physics, Faculty of Physics, Astronomy, and Informatics, Nicolaus Copernicus University, ul. Grudzia̧dzka 5, Toruń, PL 87-100, Poland; Department of Chemistry and Biochemistry and Department of Physics, University of Arizona, Tucson, Arizona 85721, USA (AMER INST PHYSICS, 2016-05-07)
      Algorithms for calculating the leading mass-velocity (MV) and Darwin (D) relativistic corrections are derived for electronic wave functions expanded in terms of n-electron explicitly correlated Gaussian functions with shifted centers and without pre-exponential angular factors. The algorithms are implemented and tested in calculations of MV and D corrections for several points on the ground-state potential energy curves of the H-2 and LiH molecules. The algorithms are general and can be applied in calculations of systems with an arbitrary number of electrons. Published by AIP Publishing.
    • Band offset in (Ga, In)As/Ga(As, Sb) heterostructures

      Gies, S.; Weseloh, M. J.; Fuchs, C.; Stolz, W.; Hader, J.; Moloney, J. V.; Koch, S. W.; Heimbrodt, W.; Univ Arizona, Coll Opt Sci (AMER INST PHYSICS, 2016-11-28)
      A series of (Ga, In)As/GaAs/Ga(As, Sb) multi-quantum well heterostructures is analyzed using temperature-and power-dependent photoluminescence (PL) spectroscopy. Pronounced PL variations with sample temperature are observed and analyzed using microscopic many-body theory and band structure calculations based on the k.p method. This theory-experiment comparison reveals an unusual, temperature dependent variation of the band alignment between the (Ga, In) As and Ga(As, Sb) quantum wells. Published by AIP Publishing.
    • Beyond the bump-hunt: A game plan for discovering dynamical dark matter at the LHC

      Dienes, Keith R.; Su, Shufang; Thomas, Brooks; Univ Arizona, Dept Phys (AMER INST PHYSICS, 2016)
      Dynamical Dark Matter (DDM) is an alternative framework for dark-matter physics in which an ensemble of individual constituent fields with a spectrum of masses, lifetimes, and cosmological abundances collectively constitute the dark-matter candidate, and in which the traditional notion of dark-matter stability is replaced by a balancing between lifetimes and abundances across the ensemble. In this talk, we discuss the prospects for distinguishing between DDM ensembles and traditional dark-matter candidates at hadron colliders - and in particular, at the upgraded LHC - via the analysis of event-shape distributions of kinematic variables. We also examine the correlations between these kinematic variables and other relevant collider variables in order to assess how imposing cuts on these additional variables may distort - for better or worse - their event-shape distributions.
    • Brillouin scattering-like effect and non-reciprocal propagation of elastic waves due to spatio-temporal modulation of electrical boundary conditions in piezoelectric media

      Croënne, C.; Vasseur, J. O.; Bou Matar, O.; Ponge, M.-F.; Deymier, P. A.; Hladky-Hennion, A.-C.; Dubus, B.; Univ Arizona, Dept Mat Sci & Engn (AMER INST PHYSICS, 2017-02-06)
      The properties of a one-dimensional phononic crystal made of identical piezoelectric elements separated by thin metallic electrodes connected to the ground are studied theoretically for cases where the locations of the electrical connections change as a function of time with a specific speed. This spatio-temporal modulation of the electrical boundary conditions results in significant non-linear effects that are evidenced numerically. The interaction between an incident harmonic longitudinal wave and the time-dependent phononic crystal is shown to lead to frequency splitting analogous to Brillouin scattering. Moreover, the boundaries of the Bragg bandgaps are strongly affected, and for some specific modulation speed, one-way wave propagation can be achieved. Published by AIP Publishing.
    • Chaos emerging in soil failure patterns observed during tillage: Normalized deterministic nonlinear prediction (NDNP) and its application

      Sakai, Kenshi; Upadhyaya, Shrinivasa K.; Andrade-Sanchez, Pedro; Sviridova, Nina V.; Univ Arizona, Dept Agr & Biol Engn (AMER INST PHYSICS, 2017-03)
      Real-world processes are often combinations of deterministic and stochastic processes. Soil failure observed during farm tillage is one example of this phenomenon. In this paper, we investigated the nonlinear features of soil failure patterns in a farm tillage process. We demonstrate emerging determinism in soil failure patterns from stochastic processes under specific soil conditions. We normalized the deterministic nonlinear prediction considering autocorrelation and propose it as a robust way of extracting a nonlinear dynamical system from noise contaminated motion. Soil is a typical granular material. The results obtained here are expected to be applicable to granular materials in general. From a global scale to nano scale, the granular material is featured in seismology, geotechnology, soil mechanics, and particle technology. The results and discussions presented here are applicable in these wide research areas. The proposed method and our findings are useful with respect to the application of nonlinear dynamics to investigate complex motions generated from granular materials. (C) 2017 Author(s).
    • Characteristic length of phonon transport within periodic nanoporous thin films and two-dimensional materials

      Hao, Qing; Xiao, Yue; Zhao, Hongbo; Univ Arizona, Dept Aerosp & Mech Engn (AMER INST PHYSICS, 2016-08-14)
      In the past two decades, phonon transport within nanoporous thin films has attracted enormous attention for their potential applications in thermoelectrics and thermal insulation. Various computational studies have been carried out to explain the thermal conductivity reduction within these thin films. Considering classical phonon size effects, the lattice thermal conductivity can be predicted assuming diffusive pore-edge scattering of phonons and bulk phonon mean free paths. Following this, detailed phonon transport can be simulated for a given porous structure to find the lattice thermal conductivity [Hao et al., J. Appl. Phys. 106, 114321 (2009)]. However, such simulations are intrinsically complicated and cannot be used for the data analysis of general samples. In this work, the characteristic length K-Pore of periodic nanoporous thin films is extracted by comparing the predictions of phonon Monte Carlo simulations and the kinetic relationship using bulk phonon mean free paths modified by K-Pore. Under strong ballistic phonon transport, K-Pore is also extracted by the Monte Carlo ray-tracing method for graphene with periodic nanopores. The presented model can be widely used to analyze the measured thermal conductivities of such nanoporous structures. Published by AIP Publishing.
    • Characterization of high-explosive detonations using broadband infrared external cavity quantum cascade laser absorption spectroscopy

      Phillips, Mark C.; Bernacki, Bruce E.; Harilal, Sivanandan S.; Brumfield, Brian E.; Schwallier, Joel M.; Glumac, Nick G.; Univ Arizona, Coll Opt Sci (AMER INST PHYSICS, 2019-09-03)
      Infrared laser absorption spectroscopy provides a powerful tool for probing physical and chemical properties of high-explosive detonations. A broadly tunable swept-wavelength external cavity quantum cascade laser operating in the mid-wave infrared (MWIR) spectral region is used to measure transmission through explosive fireballs generated from 14g charges of 4 different explosive types detonated in an enclosed chamber. Analysis of time-resolved transmission and emission at a 2 mu s sampling rate shows the evolution of fireball infrared opacity in the first 10ms after detonation. Broadband high-resolution absorption spectra acquired over the spectral range of 2050-2300cm(-1) (4.35-4.88 mu m) at a 100Hz rate are used to measure properties of fireball evolution over longer time scales out to 100s. Path-integrated concentrations of combustion products CO, CO2, H2O, and N2O are measured and show evolutions over multiple time scales and significant differences between explosive types. Spectral analysis is used to characterize gas temperature and to measure broadband attenuation from absorption and scattering of particulates. Analysis of the results provides information on the MWIR optical properties, gaseous detonation/combustion products, and particulates throughout the explosive process including initial detonation, fireball expansion and cooling, and diffusive mixing in the chamber.
    • Computational and photoelectron spectroscopic study of the dipole-bound anions, indole(H₂O)₁,₂⁻

      Buytendyk, A M; Buonaugurio, A M; Xu, S-J; Nilles, J M; Bowen, K H; Kirnosov, N; Adamowicz, L; Univ Arizona, Dept Phys; Univ Arizona, Dept Chem; Univ Arizona, Dept Biochem (AMER INST PHYSICS, 2016-07-14)
      We report our joint computational and anion photoelectron spectroscopic study of indole-water cluster anions, indole(H2O)1,2 (-). The photoelectron spectra of both cluster anions show the characteristics of dipole-bound anions, and this is confirmed by our theoretical computations. The experimentally determined vertical electron detachment (VDE) energies for indole(H2O)1 (-) and indole(H2O)2 (-) are 144 meV and 251 meV, respectively. The corresponding theoretically determined VDE values for indole(H2O)1 (-) and indole(H2O)2 (-) are 124 meV and 255 meV, respectively. The vibrational features in the photoelectron spectra of these cluster anions are assigned as the vibrations of the water molecule.
    • Computer program ATOM-MOL-nonBO for performing calculations of ground and excited states of atoms and molecules without assuming the Born-Oppenheimer approximation using all-particle complex explicitly correlated Gaussian functions

      Bubin, Sergiy; Adamowicz, Ludwik; Univ Arizona, Dept Chem & Biochem; Univ Arizona, Dept Phys (AMER INST PHYSICS, 2020-05-26)
      In this work, we describe a computer program called ATOM-MOL-nonBO for performing bound state calculations of small atoms and molecules without assuming the Born-Oppenheimer approximation. All particles forming the systems, electrons and nuclei, are treated on equal footing. The wave functions of the bound states are expanded in terms of all-particle one-center complex explicitly correlated Gaussian functions multiplied by Cartesian angular factors. As these Gaussian functions are eigenfunctions of the operator representing the square of the total angular momentum of the system, the problem separates and calculations of states corresponding to different values of the total rotational quantum number can be solved independently from each other. Due to thorough variational optimization of the Gaussian exponential parameters, the method allows us to generate very accurate wave functions. The optimization is aided by analytically calculated energy gradient determined with respect to the parameters. Three examples of calculations performed for diatomic and triatomic molecules are shown as an illustration of calculations that can be performed with this program. Finally, we discuss the limitations, applicability range, and bottlenecks of the program.
    • Contribution assessment of antenna structure and in-gap photocurrent in terahertz radiation of photoconductive antenna

      Zhang, Jitao; Tuo, Mingguang; Liang, Min; Wang, Xiong; Xin, Hao; Univ Arizona, Dept Elect & Comp Engn (AMER INST PHYSICS, 2018-08-07)
      Photoconductive antenna (PCA) is one of the most widely used terahertz (THz) devices nowadays. Although PCAs have been extensively studied through both theoretical analysis and device design, there still lacks a common agreement upon the mechanism of THz radiation. One of the central questions is how to distinguish and assess the contribution of the antenna structure and in-gap photocurrent to the overall radiation of a PCA. In this work, a three-dimensional full-wave model was first used to quantify the overall far-field radiation of PCAs. The commercial solver (i.e., HFSS) and the Hertzian dipole approximation method were then applied to quantify the far-field radiation solely from the antenna structure and in-gap photocurrent, respectively. The contribution of the antenna structure and in-gap photocurrent can therefore be distinguished by comparing the simulation results among the three methods. The results suggest that, although the THz radiation originates from laser-excited photocurrent within the gap, the overall THz radiation of a PCA is predominated by the antenna structure. As a validation, the cancellation effect was predicated by numerical simulation of coplanar stripline PCA and confirmed with experiment using butterfly shaped stripline PCA. The presented work uncovers the details of the underlying radiation mechanism of the PCA. This could inspire PCA design that aims for engineering the radiation properties of a PCA for specific applications. Published by AIP Publishing.
    • Controlling the optical spin Hall effect with light

      Lafont, O.; Luk, S. M. H.; Lewandowski, P.; Kwong, N. H.; Leung, P. T.; Galopin, E.; Lemaitre, A.; Tignon, J.; Schumacher, S.; Baudin, E.; et al. (AMER INST PHYSICS, 2017-02-06)
      The optical spin Hall effect is a transport phenomenon of exciton polaritons in semiconductor microcavities, caused by the polaritonic spin-orbit interaction, which leads to the formation of spin textures. The control of the optical spin Hall effect via light injection in a double microcavity is demonstrated. Angular rotations of the polarization pattern up to 22 degrees are observed and compared to a simple theoretical model. The device geometry is responsible for the existence of two polariton branches which allows a robust independent control of the polariton spin and hence the polarization state of the emitted light field, a solution technologically relevant for future spin-optronic devices. Published by AIP Publishing.
    • CPV generator with dish reflector and fly’s eye receiver

      Hyatt, Justin; Davila, Christian; Didato, Nicholas; Peon, Rodolfo; Rademacher, Matt; Reshidko, Dima; Sodari, Frank; Strittmatter, Peter; Vincent, Galen; Wheelwright, Brian; et al. (AMER INST PHYSICS, 2018-09-13)
      We describe a CPV generator in which an off-axis paraboloidal dish reflector powers a small receiver near the focus, housing many individually illuminated multijunction cells. The receiver entrance window doubles as a field lens that forms a reduced scale image of the reflector, at concentration of ∼30×. The image has a sharp boundary, and its position is stable against tracking errors. A fly’s eye lens array divides the image into equal portions, and further concentrates it to ∼500× onto the cells. This approach is in contrast to nearly all previous PV and CPV, where sunlight is equal apportioned (for simple series electrical connection) directly on entering the system. In our approach, small multijunction cells are packaged into a small receiver module that will be less expensive (per watt) to manufacture than large conventional PV or CPV modules, and can be economically upgraded for 40 year lifetime. Our concept differs from REhnu’s dish/receiver design [1] in its lack of obscuration and simpler cooling, using forced air convection rather than pumped liquid coolant, this made possible by the lower heat density at the cell array. In preliminary on-sun system data with a 2.4 m2 prototype powering 5.2 mm cells at 500× concentration, we demonstrate good tolerance to mispointing (90% at 0.5° off-axis), good air cooling (cell mounting plate at 19°C above ambient) and uniform division of light between the cells (scatter of 3.3% rms).
    • Creation of large temperature anisotropies in a laboratory plasma

      Beatty, C. B.; Steinberger, T. E.; Aguirre, E. M.; Beatty, R. A.; Klein, K. G.; McLaughlin, J. W.; Neal, L.; Scime, E. E.; Univ Arizona, Dept Planetary Sci (AMER INST PHYSICS, 2020-12-01)
      Ion temperature anisotropy in an expanding magnetized plasma is investigated using laser induced fluorescence. Parallel and perpendicular ion velocity distribution functions (IVDFs) were measured simultaneously with high spatial resolution in the expanding plasma. Large ion temperature anisotropies ( T perpendicular to i / T parallel to i similar to 10) are observed in a conical region at the periphery of the expanding plasma plume. A simple 2D Boris stepper model that incorporates the measured electric field structure is able to reproduce the gross features of the measured perpendicular IVDFs. A Nyquist stability analysis of the measured IVDFs suggests that multiple instabilities with k perpendicular to rho i similar to 1 and k | | rho i similar to 0.2 are likely to be excited in these plasmas.
    • Crystal alignment of a LiNi0.5Mn0.3Co0.2O2 electrode material for lithium ion batteries using its magnetic properties

      Kim, Cham; Yang, Yeokyung; Lopez, David Humberto; Ha, Dongwoo; Univ Arizona, Dept Chem & Environm Engn (AMER INST PHYSICS, 2020-09-22)
      We studied technology that enables the crystal alignment of LiNi0.5Mn0.3Co0.2O2 using its magnetic properties. LiNi0.5Mn0.3Co0.2O2 exhibited either antiferromagnetic or paramagnetic behavior depending on temperature as well as magnetic anisotropy originated from its crystallographic anisotropy. Based on these magnetic characteristics, we adjusted the vector quantity of an external magnetic field and applied it to LiNi0.5Mn0.3Co0.2O2 crystals, thus producing crystal-aligned LiNi0.5Mn0.3Co0.2O2 electrodes. In these electrodes, the (001) plane was oriented comparatively perpendicular to the surface of a current collector. Due to the intrinsic lithium ion transport kinetics in LiNi0.5Mn0.3Co0.2O2 along the (001) plane, aligned LiNi0.5Mn0.3Co0.2O2 may contribute to enhancing lithium ion conduction during the charge/discharge process in a lithium ion battery, resulting in improved electrochemical performance. Published under license by AIP Publishing.
    • Differential colorimetry measurements of fluctuation growth in nanofilms exposed to large surface thermal gradients

      Fiedler, Kevin R.; McLeod, Euan; Troian, Sandra M.; Univ Arizona, Coll Opt Sci (AMER INST PHYSICS, 2019-02-14)
      Slender liquid nanofilms exposed to large surface thermal gradients are known to undergo thickness fluctuations, which rapidly self-organize into arrays of nanoprotrusions with a separation distance of tens of microns. We previously reported good agreement between measurements of the characteristic spacing and the wavelength of the most unstable mode predicted by a linear stability analysis based on a long wavelength thermocapillary model. Here, we focus on differential colorimetry measurements to quantify early time out-of-plane growth of protrusions for peak heights spanning 20 to 200 nm. Analysis of peak heights based on shape reconstruction reveals robust exponential growth. Good quantitative agreement of the growth rates with the thermocapillary model is obtained using a single fit constant to account for material parameters of nanofilms that could not be measured directly. These findings lend further support to the conjecture that the array protrusions uncovered almost two decades ago likely stem from a linear instability, whose growth rate is controlled by thermocapillary forces counterbalanced by capillary forces. Published under license by AIP Publishing.
    • Dish-based CPV-T for rooftop generation

      Davila-Peralta, Christian; Hyatt, Justin; Alfred, Dan; Struble, Morgan; Sodari, Frank; Angel, Roger; Univ Arizona, Steward Solar Lab (AMER INST PHYSICS, 2017)
      Hybrid CPV-T with combined electrical and thermal output is well suited to solar generation from fixed limited areas, such as on the roof of an industrial or commercial facility with need for heat. This application will become especially attractive once overall electrical conversion efficiency of 40% is reached, as is projected for REhnu CPV systems using multijunction cells of 50% efficiency, anticipated in a few years. We outline here a configuration of dishbased CPV trackers optimized for close packing on a flat roof in a triangular grid, with a mirror area-to-ground area ratio of 50%. When the geometry of shadowing averaged over a year is taken into account, 80% of all the sunlight that would strike the rooftop is directed into the receivers. Such an array on a given area of flat roof will generate more electrical energy than would be possible with conventional PV panels, even if covering the entire rooftop, because of silicon's relative inefficiency. For example, in Tucson, the annual average global flux of 5.7 kWh/m2/day on a horizontal surface covered with 22% silicon modules will yield 1.25 kWh/m2/day. We show that a CPV system collecting 80% of all the direct sunlight of 7.0 kWh/m2 and converting it with 40% efficiency will yield 2.24 kWh/m2/day of rooftop area, nearly twice as much4. Thermal power will double again the total energy yield A dual axis CPV-T tracker designed specifically very close spacing has been built to carry a single dish mirror of the standard type used in REhnu's M-8 generator, described by Stalcup et al in these proceedings1,2. Sunlight is collected and focused by a single square paraboloidal mirror, 1.65 x 1.65 m with focal length of 1.5 m. For closest possible packing without mechanical interference, and for broad distribution of load on a rooftop, the mirror and receiver are mounted to a C-ring structure, configured such that the elevation and azimuth axes intersect at a virtual pivot, at the center of the sphere that just clears the receiver and the corners of the mirror. Initial tests of closed loop tracking show an accuracy of 0.03 degrees rms under calm conditions, and 0.04 degrees rms in 6 m/sec wind.
    • Effect of IrMn inserted layer on anomalous-Hall resistance and spin-Hall magnetoresistance in Pt/IrMn/YIG heterostructures

      Shang, T.; Yang, H. L.; Zhan, Q. F.; Zuo, Z. H.; Xie, Y. L.; Liu, L. P.; Zhang, S. L.; Zhang, Y.; Li, H. H.; Wang, B. M.; et al. (AMER INST PHYSICS, 2016-10-07)
      We report an investigation of anomalous-Hall resistance (AHR) and spin-Hall magnetoresistance (SMR) in Pt/Ir20Mn80/Y3Fe5O12 (Pt/IrMn/YIG) heterostructures. The AHR of Pt/IrMn/YIG heterostructures with an antiferromagnetic inserted layer is dramatically enhanced as compared to that of the Pt/YIG bilayer. The temperature dependent AHR behavior is nontrivial, while the IrMn thickness dependent AHR displays a peak at an IrMn thickness of 3 nm. The observed SMR in the temperature range of 10-300 K indicates that the spin current generated in the Pt layer can penetrate the IrMn layer (<= 3 nm) to interact with the ferromagnetic YIG layer. The lack of conventional anisotropic magnetoresistance (AMR) implies that the insertion of the IrMn layer between Pt and YIG could efficiently suppress the magnetic proximity effect (MPE) on induced Pt moments by YIG. Published by AIP Publishing.
    • Effect of low-temperature argon matrices on the IR spectra and structure of flexible N-acetylglycine molecules

      Stepanian, S. G.; Ivanov, A. Yu.; Adamowicz, L.; Univ Arizona, Dept Chem & Biochem (AMER INST PHYSICS, 2016-12)
      A study of how the matrix environment impacts the structure and IR spectra of N-acetylglycine conformers. The conformational composition of this compound is determined according to an analysis of the FTIR spectra of N-acetylglycine isolated in low temperature argon matrices. Bands of three N-acetylglycine conformers are identified based on the spectra: one major and two minor. The structure of all observed conformers is stabilized by different intramolecular hydrogen bonds. The Gibbs free energies of the conformers were calculated (CCSD(T)/CBS method), and these energy values were used to calculate conformer population at a temperature of 360 K, of which 85.3% belonged to the main conformer, and 9.6% and 5.1% to the minor conformers. We also determined the size and shape of the cavities that form when the N-acetylglycine conformers are embedded in the argon crystal during matrix deposition. It is established that the most energetically favorable cavity for the planar main conformer is the cavity that forms when 7 argon atoms are replaced. At the same time, bulky minor conformers were embedded into cavities that correspond to 8 removed argon atoms. We calculated the complexation energy between argon clusters and conformers, and the deformation energy of the argon crystal and the N-acetylglycine conformers. The matrix-induced shifts to the conformer oscillation frequency are calculated. Published by AIP Publishing.
    • The effect of matrices on the low-temperature IR spectra of a formic acid molecule isolated in inert gas crystals

      Stepanian, S. G.; Adamowicz, L.; Univ Arizona, Dept Chem & Biochem (AMER INST PHYSICS, 2020-02)
      Using the DFT/M06-2X method, we simulated the structure and vibrational spectra of inert gas (Ne, Ar, Kr, Xe) clusters with an isolated formic acid molecule. The impact of the matrix environment on the vibrational spectra of formic acid is established. The values of the matrix shifts of the vibrational frequencies predicted by calculations matched those obtained experimentally. We found that the best agreement between the calculated and experimental shifts occurred for clusters with the smallest deformation energy of the inert gas crystal. At the same time, the ratio of the volume of the molecule embedded in the matrix, and the volume of substituted matrix gas atoms, allowed one to determine only the minimum possible size of the matrix site. The calculated and experimental values of the matrix shifts are in good agreement, indicating the computation method matches the actual experimental conditions. Published under license by AIP Publishing.