Spectra Of Solutions Research Articles

Dielectric spectroscopy of solid solutions based on sodium–potassium–cadmium in the temperature range (10 ÷ 900) K

This paper studies the dielectric spectra of solid solutions (SS) of the system (1 − x − y)NaNbO3–[Formula: see text]KNbO3 –[Formula: see text]CdNb2O6 [Formula: see text]= 0.075, [Formula: see text]= 0.05 ÷ 0.30 in the temperature range (10 ÷ 900) K. The formation of a local maximum was established in the interval (260 ÷ 300) K at small [Formula: see text] values, which, as KNbO3 increases, is gradually blurred and becomes an inflection point. Detected in SS with [Formula: see text] = 0.05 ÷ 0.10, the shift of the maxima of dependences [Formula: see text]′/ [Formula: see text]0([Formula: see text]) and [Formula: see text]′′/[Formula: see text]0 ([Formula: see text]), depending on the frequency of the electric field at the temperature ranges (300 ÷ 304) K and (258 ÷ 271) K, is not related to relaxation. This anomaly may indicate a crystallographic disorder to A and B positions. The conclusion is made about the expediency of using the obtained results for the development of functional ferroactive materials.

The Wizard and the Prophet: Two Remarkable Scientists and Their Dueling Visions to Shape Tomorrow's World

The Wizard and the Prophet: Two Remarkable Scientists and Their Dueling Visions to Shape Tomorrow's World

A spectroscopic approach to identifying the out-of-plane conformations of Ni(II) meso-tetraphenylporphyrin in solution

Ni(II) meso-tetraphenylporphyrin (NiTPP) is a model molecule whose substituent causes out-of-plane (oop) deformations of the porphyrin macrocycle. Although the conformers of NiTPP in the solution had been tentatively explored, the determination of its specific conformers was controversial. In this work, based on the conformational search through molecular dynamics (MD), three energy lowest-lying conformers of NiTPP were sorted out, namely, the S4 (staggered) conformer, the C2 (eclipsed) conformer, and the C1 (eclipsed-staggered) conformer. According to the high-precision free energy calculation based on density functional theory (DFT), the Raman and 1H-NMR spectra of the three conformers were calculated. The actual spectra of NiTPP in solution resulted from the sum spectra of the mixture conformers, so with the consideration of the corresponding conformation weights, the experimental spectra could be stimulated. Our results showed that only at the low-frequency ∼215 cm−1, did the Raman spectrum in solution differ significantly from that in solid powder. On the other hand, the 1H-NMR spectra of the NiTPP conformers were remarkably different, and none of the single conformer's 1H-NMR range could match the experimental 1H-NMR spectrum. However, with the consideration of the existence of three dominant conformations, the observed 1H-NMR spectrum could be well simulated, confirming the rational mixture of the three dominant conformers existing in the aqueous solution. Therefore, this work has not only resolved the different conformers of NiTPP in solution, but also provided an effective approach to combining DFT, Raman, and 1H-NMR analytical tools for identifying different oop conformations of metalloporphyrins in solution.

Accurate Vertical Ionization Energy of Water and Retrieval of True Ultraviolet Photoelectron Spectra of Aqueous Solutions.

Ultraviolet (UV) photoelectron spectroscopy provides a direct way of measuring valence electronic structure; however, its application to aqueous solutions has been hampered by a lack of quantitative understanding of how inelastic scattering of low-energy (<5 eV) electrons in liquid water distorts the measured electron kinetic energy distributions. Here, we present an efficient and widely applicable method for retrieving true UV photoelectron spectra of aqueous solutions. Our method combines Monte Carlo simulations of electron scattering and spectral inversion, with molecular dynamics simulations of depth profiles of organic solutes in aqueous solution. Its application is demonstrated for both liquid water, and aqueous solutions of phenol and phenolate, which are ubiquitous biologically relevant structural motifs.

Quaternary Ammonium Salts Interact with Enolates and Sulfonates via Formation of Multiple +N-C-H Hydrogen Bonding Interactions

We report herein sharp physical evidence, i.e., single-crystal X-ray diffraction and 1H-NMR spectral data, confirming that quaternary ammonium species interact with anions via a set of directional ion–dipole cooperative +N-C-H unusual H-bonding interactions and not via pure non-directional ionic electrostatic interactions. This finding, which has been often invoked by calculations, is herein substantiated by the preparation of two model compounds and an analysis of their X-ray crystal structures in the solid state and 1H-NMR spectra in solution. These observations are particularly pertinent for the rational design of novel catalyses and catalysts and providing guidance to an understanding of these species in solution and during asymmetric enantioselective catalysis.

Probing electrolyte-silica interactions through simulations of the infrared spectroscopy of nanoscale pores.

The structural and dynamical properties of nanoconfined solutions can differ dramatically from those of the corresponding bulk systems. Understanding the changes induced by confinement is central to controlling the behavior of synthetic nanostructured materials and predicting the characteristics of biological and geochemical systems. A key outstanding issue is how the molecular-level behavior of nanoconfined electrolyte solutions is reflected in different experimental, particularly spectroscopic, measurements. This is addressed here through molecular dynamics simulations of the OH stretching infrared (IR) spectroscopy of NaCl, NaBr, and NaI solutions in isotopically dilute HOD/D2O confined in hydroxylated amorphous silica slit pores of width 1-6nm and pH ∼2. In addition, the water reorientation dynamics and spectral diffusion, accessible by pump-probe anisotropy and two-dimensional IR measurements, are investigated. The aim is to elucidate the effect of salt identity, confinement, and salt concentration on the vibrational spectra. It is found that the IR spectra of the electrolyte solutions are only modestly blue-shifted upon confinement in amorphous silica slit pores, with both the size of the shift and linewidth increasing with the halide size, but these effects are suppressed as the salt concentration is increased. This indicates the limitations of linear IR spectroscopy as a probe of confined water. However, the OH reorientational and spectral diffusion dynamics are significantly slowed by confinement even at the lowest concentrations. The retardation of the dynamics eases with increasing salt concentration and pore width, but it exhibits a more complex behavior as a function of halide.

AdS-Taub-NUT spacetimes and exact black bounces with scalar hair

We present a new family of exact four-dimensional Taub-NUT spacetimes in Einstein-$\Lambda$ theory supplemented with a conformally coupled scalar field exhibiting a power-counting super-renormalizable potential. The construction proceeds as follows: A solution of a conformally coupled theory with a conformal potential, henceforth the seed $(g_{\mu\nu},\phi)$, is transformed by the action of a specific change of frame in addition with a simultaneous shift of the seed scalar. The new configuration, $(\bar{g}_{\mu\nu},\bar{\phi})$, solves the field equations of a conformally coupled theory with the aforementioned super-renormalizable potential. The solution spectrum of the seed is notoriously enhanced. We highlight the existence of two types of exact black bounces given by de Sitter and anti-de Sitter geometries that transit across three different configurations each. The de Sitter geometries transit from a regular black hole with event and cosmological horizons to a bouncing cosmology connecting two de Sitter Universes with different values of the asymptotic cosmological constant. An intermediate phase represented by a de Sitter wormhole or by a bouncing cosmology that connects two de Sitter Universes is shown, this under the presence of a cosmological horizon. On the other hand, the anti-de Sitter geometries transit from a regular black hole with inner and event horizons to a wormhole that connects two asymptotic boundaries with different constant curvatures. The intermediate phase is given by an anti-de Sitter regular black hole with a single event horizon that appears in two different settings. As a regular anti-de Sitter black hole inside of an anti-de Sitter wormhole or as an anti-de Sitter regular black hole with an internal cosmological bounce. These geometries are smoothly connected by the mass parameter only. Other black holes, bouncing cosmologies and wormholes are also found.

Robust route to H2O2 and H2 via intermediate water splitting enabled by capitalizing on minimum vanadium-doped piezocatalysts.

H2O2 is an environmentally friendly chemical for a wide range of water treatments. The industrial production of H2O2 is an anthraquinone oxidation process, which, however, consumes extensive energy and produces pollution. Here we report a green and sustainable piezocatalytic intermediate water splitting process to simultaneously obtain H2O2 and H2 using single crystal vanadium (V)-doped NaNbO3 (V-NaNbO3) nanocubes as catalysts. The introduction of V improves the specific surface area and active sites of NaNbO3. Notably, V-NaNbO3 piezocatalysts of 10 mg exhibit 3.1-fold higher piezocatalytic efficiency than the same catalysts of 50 mg, as more piezocatalysts lead to higher probability of aggregation. The aggregation causes reducing active sites and decreased built-in electric field due to the neutralization between different nano-catalysts. Remarkably, piezocatalytic H2O2 and H2 production rates of V-NaNbO3 (10 mol%) nanocubes (102.6 and 346.2 µmol·g−1·h−1, respectively) are increased by 2.2 and 4.6 times compared to the as-prepared pristine NaNbO3 counterparts, respectively. This improved catalytic efficiency is attributed to the promoted piezo-response and more active sites of NaNbO3 catalysts after V doping, as uncovered by piezo-response force microscopy (PFM) and density functional theory (DFT) simulation. More importantly, our DFT results illustrate that inducing V could reduce the dynamic barrier of water dissociation over NaNbO3, thus enhancing the yield of H2O2 and H2. This facile yet robust piezocatalytic route using minimal amounts of catalysts to obtain H2O2 and H2 may stand out as a promising candidate for environmental applications and water splitting.Electronic Supplementary MaterialSupplementary material (typical Raman spectra of NaNbO3 and V-NaNbO3 with various doping concentrations (Fig. S1). XPS spectra of Na 1s (Fig. S2). PL spectra of solution obtained from the piezocatalytic system using NaNbO3 and V-NaNbO3 (10 mol%) as the catalysts after 1 h (Fig. S3). The length of NaNbO3 and V-NaNbO3 nanocubes calculated from XRD data of their (101) planes (Table S1)) is available in the online version of this article at 10.1007/s12274-022-4506-0.

UV spectra of aqueous or ethanolic solutions of twenty-seven active pharmaceutical ingredients

UV spectra of aqueous or ethanolic solutions of twenty-seven active pharmaceutical ingredients

The sustainability of health economics: Proceedings from the 2022 Inter-University Big Data Challenge

STEM Fellowship’s Inter-University Big Data Challenge is a unique Big Data inquiry and experiential learning program that provides university students worldwide an opportunity to apply computational thinking in search of national, regional, community, and individual health solutions. It is a new form of R&amp;D talent development and identification through computational science and scholarly communication demonstrated by students. As part of the program, participants were offered a broad range of workshops in data analytics, programming, and science communication. Some of the tools the students learned and used include Python, R, machine learning, LaTeX, and Overleaf. This year, the program participants explored issues of The Sustainability of Health Economics and suggested a whole spectrum of original Open Data-based ideas and solutions. Presented research topics are ranging from Improved Health Resource Allocation and Tracking the Spread of a Virus to Health Insurance based on Health Behaviours, and more. Overall, we received submissions from student teams from practically all leading Canadian universities, mixed teams of students from Canada and the US, Asian, and Latin American universities. On behalf of the STEM Fellowship, we extend our sincere congratulations to all students who participated in the program and wish them the best for their future academic and professional endeavours. We want to express our appreciation to all the mentors and volunteers. This program would not be possible without generous support of our sponsors: Hoffman La Roche Canada, Canadian Science Publishing, and JMIR Publications.

A new tripodal 8-hydroxyquinoline as a high sensitivity fluorescence sensor for Zn(II) in ethanol and its two morphology in solid

New tripodal ligand form two different dinuclear Zn 2+ complex in solid, but identical in solution. The strong chelate significantly increased fluorescence sensitivity toward Zn 2+ in ethanol solution. • New tripodal ligands (HL) were synthesized from 8-hydroxyquinoline and bis(pyridin-2-ylmethyl)amine. • HL forms stable Zn(II) complexes which has very strong fluorescence in ethanol. The LOD for Zn(II) fluorescence is 2.3 nM. • Symmetric/asymmetric dinuclear Zn(II) complexes with identical formulae can be isolated from CH 3 CN solution, but they are identical in solution. A new tripodal chelate HL was synthesized from tridentate chelate bis(pyridin-2-ylmethyl)amine (BPA) and 8-hydroxyquinoline (8-HQ) to increase interaction between HL and Zn 2+ and improve fluorescence sensitivity. Asymmetric and symmetric dinuclear Zn(II) complex in rod and block shape were formed in CH 3 CN with identical formula, 1 H NMR and fluorescence spectra in solution, but different IR, TG, and PXRD in solid. The fluorescence quantum yields are 0.0145 and 0.602 for HL and [ZnL] 2 2+ in ethanol respectively. LOD reached 2.3 nM Zn 2+ , which is the highest sensitivity. The 7-position functionalization of 8-HQ is critical to the strong coordination and high fluorescence sensitivity.

Synthesis of Silver Nanoparticles using Nigella sativa Seed Extract and its Efficacy Against Some Multidrug-Resistant Uropathogens

Background: Urinary tract infection (UTI) is one of the most chronic infections in humans, as well as the most common cause of multidrug-resistant (MDR) pathogen emergence, necessitating the quest for stringent antibiotic treatment. In the imperative search for effective drugs to combat MDR, silver nanoparticles (AgNPs) are given priority. The objective of this study was to synthesize, characterize, and evaluate the antimicrobial activity of AgNPs synthesized using Nigella sativa on MDR uropathogens. Methods: Urine samples of suspected UTI patients were collected using sterile sample bottles and cultured on different agar media to isolate and identify uropathogens using conventional method. All isolates were screened for multidrug resistance by disk diffusion method following the Clinical and Laboratory Standards Institute guideline with slight modification. N. sativa seed extract was used to synthesize AgNPs from aqueous solution of silver nitrate (AgNO3). AgNPs formed were characterized using ultraviolet-visible (UV-Vis) spectroscopy, scanning electron microscope (SEM), dynamic light scattering, Fourier transform infrared spectroscopy, and X-ray diffraction spectroscopy (XRD). Antibacterial activities of synthesized AgNPs were assessed (in vitro) by disc diffusion method against MDR isolates, and cytotoxicity was evaluated using brine shrimp lethality assay. The formed AgNPs were characterized using UV-Vis, and antibacterial activity of synthesized AgNPs was assessed (in vitro) by impregnated disc diffusion method against MDR isolates. Results: Escherichia coli, Klebsiella sp., and Staphylococcus aureus were isolated. Multiple antibiotic-resistant indexes of the isolates ranged between 0.4 and 0.75 against the different standard antibiotics tested. The color change from pale yellow to dark brown was indicative of AgNP formation. UV-Vis spectrum of solution containing AgNPs exhibited peak wavelengths of 378 nm. Fourier transform infrared spectroscopic analysis showed that terpenoids, flavonoid, and phenols played an important role in the biosynthesis. Irregular shapes within nanoscale range were detected using SEM. XRD showed that the particles were crystalline in structure with an average size of 32 nm. The mean diameter zone of inhibition (in mm) for the different isolates at the dose of 100 μg/mL concentration showed maximum for E. coli (18 mm) followed by both Klebsiella sp. and S. aureus at 17 mm. Conclusion: The study underscores the efficacy of the plant-mediated nanoparticles as well as their potential for use as broad-spectrum antimicrobial agents for the management of MDR uropathogens.

Thirring İnstantonlarının Lyapunov Üstelleri

Recently, nonlinear differential equations corresponding to pure spinor instanton solutions were obtained by using Heisenberg anzat in the 2D Thirring Model, which has been used as a toy model in Quantum field theory. In addition, the evolution of spinor type instanton solutions in phase space was investigated according to the change in the constant parameter β. Spinor instanton dynamics is a special case in which nonlinear terms play an important role. Chaos describes certain nonlinear dynamical systems that depend very precisely on initial conditions. Lyapunov exponents are an important method for measuring stability and deterministic chaos in dynamical systems. Lyapunov exponents characterize and quantify the dynamics of small perturbations of a state or orbit in state space. In this study, Lyapunov spectrum of spinor type instanton solutions was investigated by examining the largest local and global Lyapunov exponents. As a result of the Lyapunov Spectrum, it was determined that the spinor type instanton solutions exhibit chaotic behavior at parameter value β = 2. Periodic and quasi periodic behaviors were detected when the parameter values were β &lt; 2. In cases of β &gt; 2, weak chaotic behaviors were observed. This study demonstrates that Thirring Instantons, which are spinor type instanton solutions, exhibit chaotic properties.

Effect of RGUP on the nonlinear Klein-Gordon model with spontaneous symmetry breaking

In the framework of the relativistic generalized uncertainty principle (RGUP), we study the nonlinear Klein-Gordon field with ϕ4 self-interaction. This generalization comes from the quantum gravity theories that predict the existence of a minimal measurable length scale. The quantum gravity effects slightly modify the momentum and change the Lagrangian density of the field. This model, specifically in the context of spontaneous symmetry breaking, is so fruitful and leads us to many interesting phenomena. Due to the complexity of the consequent equations, the model is normally studied via perturbation mechanisms. However, here, we apply a generalized tanh-method which supposed that the field solutions should be sech-functions of segments of space and time. By this extended method, we find some more general solutions with respect to our previous work [1]. Several solutions can be found but we select only the normalizable and bounded solitary fields. The energy spectrum of each field solution is obtained in an analytical form and discussed. The modification parameter of the corresponding RGUP is estimated by using the rest energy of the mass of the Higgs boson.

Growth and Nutrient Utilization in Basil Plant as Affected by Applied Nutrient Quantity in Nutrient Solution and Light Spectrum

Simple SummaryThe growth and nutrient utilization of hydroponic vegetables are largely affected by the nutrient solution management method and light environment. This study was conducted to improve the growth, nutrient absorption efficiency, and nutrient use efficiency of basil plants grown in a plant factory with artificial lighting by controlling the nutrient solution management method and light spectrum. Basil plants were treated with 4 applied nutrient quantities and three red:blue ratios from transplanting to harvest (20 days). Results showed that low applied nutrient quantity significantly improved the nutrient use efficiency and nutrient absorption efficiency. Furthermore, the yield of the basil plant and the absorption of N and K were significantly influenced by different red:blue ratios under low applied nutrient quantity treatments. Therefore, this study has determined the optimal combination of the applied nutrient quantity and red:blue ratio for improving the growth, nutrient use efficiency, and nutrient absorption efficiency of basil plants. The findings of this study can be applied to hydroponic basil production for saving resources and protecting the environment.Quantitative nutrient management has advantages, such as saving resources and improving nutrient utilization, compared with the conventional electrical conductivity management method. The growth and nutrient utilization of vegetables are affected by the integrated environmental conditions such as nutrient supply and light spectrum. This study investigated the effects of applied nutrient quantity (ANQ) (0.5, 1, 2, and 4 times (T) the absorption quantity of nutrients determined in the preliminary experiment, indicated by 0.5T, 1T, 2T, and 4T, respectively) in nutrient solution and red:blue ratio (R:B = 3:7, 7:3, and 9:1, indicated by RB3:7, RB7:3, and RB9:1, respectively) on the growth and nutrient utilization of basil plants in a plant factory with artificial lighting. Results demonstrated that the nutrient use efficiency (NUE) and the nutrient absorption efficiency (NAE) were significantly increased by the ANQ of 0.5T compared with the treatments of 1T, 2T, and 4T, irrespective of R:B ratios. Furthermore, under the ANQ of 0.5T, RB7:3 significantly increased the yield and the absorption of N and K of the basil plant compared with other R:B ratios. Therefore, the ANQ of 0.5T combined with RB7:3 was considered the optimal combination to improve the yield, NUE, and NAE of basil plants in the present study.

Using Sampling to Estimate and Improve Performance of Automated Scoring Systems with Guarantees

Automated Scoring (AS), the natural language processing task of scoring essays and speeches in an educational testing setting, is growing in popularity and being deployed across contexts from government examinations to companies providing language proficiency services. However, existing systems either forgo human raters entirely, thus harming the reliability of the test, or score every response by both human and machine thereby increasing costs. We target the spectrum of possible solutions in between, making use of both humans and machines to provide a higher quality test while keeping costs reasonable to democratize access to AS. In this work, we propose a combination of the existing paradigms, sampling responses to be scored by humans intelligently. We propose reward sampling and observe significant gains in accuracy (19.80% increase on average) and quadratic weighted kappa (QWK) (25.60% on average) with a relatively small human budget (30% samples) using our proposed sampling. The accuracy increase observed using standard random and importance sampling baselines are 8.6% and 12.2% respectively. Furthermore, we demonstrate the system's model agnostic nature by measuring its performance on a variety of models currently deployed in an AS setting as well as pseudo models. Finally, we propose an algorithm to estimate the accuracy/QWK with statistical guarantees (Our code is available at https://git.io/J1IOy).

Circular Dichroism Spectra of α-Chymotrypsin-SDS Solutions Depend on the Procedure of Their Preparation.

We recorded the far- and near-UV circular dichroism (CD) spectra of solutions of α-chymotrypsin and sodium dodecyl sulfate (SDS) with the final surfactant concentration significantly above the critical micellization concentration. Solutions were prepared using three different procedures. The reference procedure was to mix the chymotrypsin solution with the SDS solution once, immediately achieving the final SDS concentration. In alternative procedures, the protein solutions initially contained some SDS and were mixed with pure SDS solutions at a concentration to provide the same final surfactant as the reference mixing. We demonstrate that the supplementation to the selected final concentration of SDS of the pure chymotrypsin solution leads to different CD spectra than the supplementation to this final concentration of SDS in the chymotrypsin solution containing a small concentration of a few millimolar SDS. These differences disappear when the initial concentration of SDS in the protein solution, which we then supplement to the indicated final concentration, is higher. This suggests the irreversibility of the processes caused by the addition of SDS to chymotrypsin and the influence of the initial amount of this surfactant on the processes occurring with its further addition to the solution. For quantitative analysis of far-UV CD spectra in terms of populations of protein secondary structure elements, we used four well-established software packages. All programs consistently indicate that the observed differences in the far-UV CD spectra can be explained by the differences in the increase in the population of helical forms in chymotrypsin under the influence of SDS.

Determination of copper and lead ions using gold nanoparticles as a colorimetric probe with the aid of cysteine

Determination of copper and lead ions using gold nanoparticles as a colorimetric probe with the aid of cysteine

Synthesis of Water-Soluble Planar Cobalt(II), Nickel(II), and Copper(II) Hydroxo Clusters Using a (1,4,7-Triazacyclononane)cobalt(III) Complex as a Hydrolysis-Terminating Group.

We report on a group of planar cobalt(II), nickel(II), and copper(II) hydroxo clusters that have a definite composition and are water-soluble: [{Co(tacn)(OH)2}6Co7(OH)12](NO3)2(CF3SO3)6·10H2O (1), [{Co(tacn)(OH)2}6Ni7(OH)12](NO3)2(CF3SO3)6·10H2O (2a), [{Co(tacn)(OH)2}6Ni7(OH)12](BNPP)8·6CH3NO2·8H2O [2b; BNPP = bis(p-nitrophenyl)phosphate], [{Co(tacn)(OH)2}12Ni16(OH)26(OH2)2](SO4)4(CF3SO3)10·30H2O (3a), [{Co(tacn)(OH)2}12Ni16(OH)26(OH2)2](SO4)8(CF3SO3)2·44H2O (3b), [{Co(tacn)(OH)2}2Co2(OH)2(OH2)4](SO4)(CF3SO3)2·4H2O (4), [{Co(tacn)(OH)2}2Ni2(OH)2(OH2)4](SO4)(CF3SO3)2·4H2O (5), and [{Co(tacn)(OH)2}4Cu4(OH)6](ClO4)6·5H2O (6), where tacn is 1,4,7-triazacyclononane. The peripheral of each metal hydroxo cluster plane is chemically protected by the coordination of {CoIII(tacn)(OH)2}+ groups to prevent further hydrolysis. These clusters were synthesized by the reaction of an equimolar amount of [Co(tacn)(OH2)3]3+ and cobalt, nickel, or copper salt at pH values in the range of 6.0-12.0. The structure of the cation in compounds 1, 2a or 2b, 4, and 5 is relevant to the surface structure of the cobalt phosphate and nickel borate oxygen-evolution catalysts; in particular, the Co7(OH)12 core in 1. Moreover, the arrangement of M7(OH)12 in 1 and 2a or 2b and Cu4(OH)6 in 6 represents the solid-state structures of the (111) face of the cubic CoO or NiO and the (002) plane of Cu(OH)2, respectively. Extended X-ray absorption fine structure spectra of an aqueous solution of 1, 2a, 4, and 5 exhibit well-resolved peaks at the first and second coordination spheres due to the M-O and M···M distances, respectively; the solution-state bond distances were estimated, and they agreed well with the bond distances in the solid-state structures.

Infrared bands of formaldehyde dissolved in liquid krypton at cryogenic temperatures and the vibrational modes ν1, ν2, and ν5 of H2CO in comets and interstellar clouds

The infrared spectra of formaldehyde (H2CO) dissolved in liquid krypton between 125 K and 137 K have been obtained using a Fourier transform infrared spectrophotometer and a low temperature cryostat. Backing pressures higher than 1.5 atm were necessary to liquefy Kr above 120 K. Monomeric formaldehyde in gas phase was prepared by thermal decomposition of para-formaldehyde. Peak positions (ν), wavenumber shifts between the gas and liquid solution spectra (Δν), and full widths at half maximum (fwhm) are reported. The H2CO vibrational frequencies in liquid Kr are slightly lower than the gas phase frequencies at room temperature because of the inertness of the solvent. The Gaussian 16 software package is used to determine the geometry and lowest energy of H2CO at room temperature and at the temperature of the experiment. Fundamental harmonic and anharmonic vibrational frequencies and relative intensities are calculated. The influence of the solvent on fundamental vibrational frequencies is studied using the polarizable continuum model (PCM). When used in conjunction with calculated anharmonic frequencies, the PCM model shows qualitative agreement with experimental frequency shifts and relative intensities in liquid Kr. The presence of H2CO in space is discussed in reference to the ν1 and ν5 absorption bands observed in comets, the ν1 and ν2 absorptions in interstellar clouds, and the lack of detection of the ν4 and ν6 bands of H2CO in the atmosphere of Titan. The carbonyl stretching mode ν2 is suggested as a possible candidate for confirmation and identification of H2CO in space due to its larger strength in comparison to the other modes that have been studied at low temperatures and its characteristic frequency that is completely removed from CO2, CO, H2O and CH3OH vibrational modes.