Deuterium Bonds Research Articles

Study of polarized IR spectra of the hydrogen bond system in crystals of styrylacetic acid

We have investigated the polarized IR spectra of the hydrogen bond system in crystals of trans-styrylacetic acid C 6H 5 CH CH CH 2 COOH, and also in crystals of the following three deuterium isotopomers of the compound: C 6H 5 CH CH CH 2 COOD, C 6H 5 CH CH CD 2 COOH and C 6H 5 CH CH CD 2 COOD. The spectra were measured at room temperature and at 77 K by a transmission method. The spectral studies were preceded by determination of the X-ray crystal structure. Theoretical analysis of the results concerned linear dichroic effects, the H/D isotopic and temperature effects, observed in the solid-state IR spectra of the hydrogen and of the deuterium bond, at the frequency ranges of the ν O H and the ν O D bands, respectively. Basic spectral properties of the crystals can be interpreted satisfactorily in terms of the “ strong-coupling” theory, when based on a hydrogen bond dimer model. This model sufficiently explained not only a two-branch structure of the ν O H and the ν O D bands, and temperature-induced evolution of the crystalline spectra, but also the linear dichroic effects observed in the band frequency ranges. A vibronic mechanism was analyzed, responsible for promotion of the symmetry-forbidden transition in the IR for the totally symmetric proton stretching vibrations in centrosymmetric hydrogen bond dimers. It was found to be of minor importance, when compared with analogous spectral properties of arylcarboxylic acid, or of cinnamic acid crystals. These effects were ascribed to a substantial weakening of electronic couplings between the hydrogen bonds of the associated carboxyl groups and the styryl radicals, associated with the separation of these groups in styrylacetic acid molecules by methylene groups in the molecules.

H/D isotopic “self-organization” effects in the infrared spectra of cyclic tetramers of hydrogen bonds: Polarized spectra of 7-azaindole crystals

This paper presents the results of our investigation of the polarized IR spectra of the hydrogen bond in the 7-azaindole crystals. These spectra were measured at room temperature and at 77 K by a transmission method, using polarized light. Theoretical analysis of the results concerned linear dichroic effects, and the H/D isotopic and temperature effects, observed in the solid-state IR spectra of the hydrogen and of the deuterium bond, at the frequency ranges of the ν N–H and the ν N–D bands, respectively. Basic spectral properties of the crystals can be interpreted satisfactorily in a quantitative way in terms of the “ strong-coupling” theory. This model sufficiently explains a two-branch structure of the ν N–H and the ν N–D bands in the crystalline spectra, but also some of the isotopic dilution effects, observed in the band frequency ranges, in the spectra of 7-azaindole crystals. Within the scope of our studies, the mechanism of the H/D isotopic “ self-organization” processes in the crystal hydrogen bonds was also recognized. When working with spectra of isotopically diluted crystalline samples of 7-azaindole, it was proved that a non-random distribution of the protons and deuterons occurs in the cyclic tetramers of hydrogen-bonded molecules. In isotopically diluted crystalline samples, in one four-membered hydrogen bond ring of associated 7-azaindole, only four identical hydrogen isotope atoms can stable exist. The electronic structure of these compounds was considered as responsible for relatively strong dynamical inter-hydrogen bond co-operative interactions, which was the reason of appearance of the H/D isotopic “ self-organization” effects in the hydrogen bond IR spectra.

Deep traps in oxide-nitride-oxide stacks fabricated from hydrogen and deuterium containing precursors

The energy spectrum of the traps and thermal stability of stored charge have been studied by the thermostimulated exoelectron emission method in hydrogenated H and deuterated D oxide-nitride-oxide (ONO) multilayer stacks of silicon-oxide-nitride-oxide-silicon (SONOS) nonvolatile memories. It is shown that the trap energies are identical for both types of ONO. The deep traps responsible for charge storage have an activation energy 1.7–1.8 eV and are attributed to complexes containing excess silicon with chemically bonded hydrogen or deuterium atoms. It was found that the stability of the deep traps in D-ONO stacks is much higher than in standard H-ONO. It is supposed that the observed isotopic effect is related to different vibration dynamics of hydrogen bonds compared with deuterium bonds.

Vibronic model for H/D isotopic “self-organization” effects in hydrogen bond cyclic trimeric systems: 4-Bromopyrazole crystal IR spectra

In this paper, a theoretical model has been proposed, aiming to explain a new kind of H/D isotopic effects concerning hydrogen bond systems, i.e. the H/D isotopic “self-organization” effects, recently deduced from the IR spectra of molecular crystals. The problem of existence of these kinds of co-operative effects was considered in the limits of a vibronic model in the Herzberg–Teller approximation, for cyclic trimeric systems of hydrogen bonds. It was shown that non-conventional attraction forces between three identical hydrogen isotope atoms, resulting from the vibronic mechanism, are responsible for excess stabilization energy of cyclic hydrogen bond trimers. The H/D “self-organization” effects were deduced to be negligible in the case of non-symmetric HDD, or HHD-type trimers, containing both, hydrogen and deuterium bonds in one ring trimer. The symmetric trimers of the HHH and of the DDD-type should be more stable, when compared with the HDD, or the HHD-type trimer properties. This thermodynamic effect explains the IR spectral properties of molecular crystals containing cyclic trimers of hydrogen bonds in their lattices, accompanying to isotopic dilution. The results of the theoretical considerations were confronted with the IR spectra of 4-bromopyrazole crystals, which were measured in a wide temperature range (from 298 to 77 K), using polarized light, in the frequency ranges of the proton or deuterium stretching vibrations bands.

수소 및 중수소가 포함된 실리콘 산화막의 전기적 스트레스에 의한 열화특성

Experimental results are presented for the degradation of 3 nm-thick gate oxide <TEX>$(SiO_2)$</TEX> under both Negative-bias Temperature Instability (NBTI) and Hot-carrier-induced (HCI) stresses using P and NMOSFETS, The devices are annealed with hydrogen or deuterium gas at high-pressure <TEX>$(1\~5\;atm.)$</TEX> to introduce higher concentration in the gate oxide. Both interface trap and oxide bulk trap are found to dominate the reliability of gate oxide during electrical stress. The degradation mechanism depends on the condition of electrical stress that could change the location of damage area in the gate oxide. It was found the trap generation in the gate oxide film is mainly related to the breakage of Si-H bonds in the interface or the bulk area. We suggest that deuterium bonds in <TEX>$SiO_2$</TEX> film are effective in suppressing the generation of traps related to the energetic hot carriers.

High-resolution spectroscopy of induced chiral dimers: A study of the dimers of ethanol by Fourier transform microwave spectroscopy

We present the first recording of the high-resolution spectrum of an induced chiral dimer. Three conformers of the induced chiral dimers of ethanol have been observed using a pulsed molecular-beam Fourier transform microwave spectrometer. The rotational constants of the normal isotopomers of the three species have been determined to be (a) A=5113.826(5), B=1329.7214(4), and C=1257.5151(3) MHz, (b) A=5086.459(5), B=1316.6508(4), and C=1243.6329(4) MHz, and (c) A=4851.608(5), B=1369.7558(6), and C=1243.4184(4) MHz. The observed species have been assigned to calculated structures via Kraitchman double substitution analyses and ab initio calculations. The Kraitchman analyses and the fitted centrifugal distortion parameters suggest that the deuterium bond is significantly stronger than the hydrogen bond in the dimers of ethanol.

On the structure and spectroscopic properties of two 13-hydroxylupanine epimers

The crystal structures of 13α- and 13β-hydroxylupanines present a rare case of unexpected configuration and conformation of bis-quinolizidine alkaloid free bases. The configuration of A/B and C/D ring junctions is trans– cis and quasi trans– cis in α and β epimers, respectively. Ring C adopts a distorted chair form in both of them which is unusual for lupin alkaloids free bases. Such a drastic rearrangement of electronic configuration at N16 is caused by intermolecular hydrogen bonds formation between the OH and C O groups. In spite of different orientations of the OH groups - an axial or an equatorial in α and β epimers, respectively, the hydrogen bond geometry is the same in both crystal structures. This causes different distortions in all four rings of bis-quinolizidine skeletons. The Duax-Norton approach has been used to analyze them. In solution, both epimers occur in conformational equilibrium with considerable domination of the C-boat conformer (85–90%). This conformation is stabilized by the other type of intermolecular hydrogen bonds in comparison with that operating in the solid. Intermolecular deuterium bonds between 13α- and/or 13β-hydroxylupanine molecules and the solvent CDCl 3 molecules as well as the N16⋯H–O association have been found to play a crucial role.

Effect of deuterium oxide on the thermodynamic quantities associated with phase transitions of phosphatidylcholine bilayer membranes

The bilayer phase transitions of three kinds of phospholipids, dipalmitoylphosphatidylcholine (DPPC), distearoylphosphatidylcholine (DSPC) and dihexadecylphosphatidylcholine (DHPC), in deuterium oxide (D 2O) and hydrogen oxide (H 2O) were observed by differential scanning calorimetry (DSC) under ambient pressure and light-transmittance measurements under high pressure. The DSC measurements showed that the substitution of H 2O by D 2O affected the pretransition temperatures and the main-transition enthalpies of all PC bilayers. The temperature–pressure phase diagrams for these PC bilayer membranes in both solvents were constructed by use of the data of light-transmittance measurements. Regarding the main transition of all PC bilayer membranes, there was no appreciable difference between the transition temperatures in D 2O and H 2O under high pressure. On the other hand, the phase transitions among the gel phases including the pretransition were significantly affected by the solvent substitution. The thermodynamic quantities of phase transitions for the PC bilayer membranes were evaluated and the differences in thermodynamic properties by the water substitution were considered from the difference of interfacial-free energy per molecule in the bilayer in both solvents. It was proved that the substitution of H 2O by D 2O causes shrinkage of the molecular area of phospholipid at bilayer interface due to the difference in bond strength between deuterium and hydrogen bonds and produces the great influence on the bilayer phase with the smaller area. Further, the induction of bilayer interdigitation in D 2O turned out to need higher pressures than in H 2O.

Strong coupling effects in the polarized IR spectra of the chain hydrogen bond systems in 3-pyridinealdoxime and 4-pyridinealdoxime crystals: H/D isotopic self-organization effects in the IR spectra

This paper presents the results of our investigation with the polarized IR spectra of the hydrogen bond in the 3-pyridinealdoxime and 4-pyridnealdoxime crystals, and also in the crystals of the deuterium derivatives of these two compounds. In each case these spectra were measured for the two different crystalline faces at room temperature and at 77 K by a transmission method, using the polarized light. Theoretical analysis of the results concerned linear dichroic effects, and the H/D isotopic and temperature effects, observed in the solid-state IR spectra of the hydrogen and the deuterium bond, at the frequency ranges of the ν O–H and the ν O–D bands. Basic spectral properties of the crystals can be interpreted in a satisfactory quantitative way for a hydrogen bond linear dimer model in terms of the ‘ strong-coupling’ theory. This model explains not only a two-branch structure of the ν O–H and the ν O–D bands in the crystalline spectra, but also some essential linear dichroic effects in the band frequency ranges, for isotopically diluted crystals. Within the scope of our studies, the mechanism of the H/D isotopic self-organization processes (which take place in the crystalline hydrogen bond lattices) was also recognized. It was proved that for isotopically diluted crystalline samples of 3-pyridinealdoxime and 4-pyridnealdoxime, a non-random distribution of the protons and deuterons occurs exclusively in some restricted fragments (i.e. domains) of open chains of the hydrogen bonded molecules. Nevertheless, these co-operative interactions between the hydrogen bonds do not concern the adjacent fragments of the neighboring hydrogen bond chains in the lattice. The electronic structure of these compounds was considered as responsible for such co-operative effects of the hydrogen bonds.

Strong coupling effects in the polarized IR spectra of the chain hydrogen bond systems in imidazole crystals: H/D isotopic ‘self-organization’ effects in the IR spectra of isotopically diluted imidazole single crystals

This paper presents the investigation results of the polarized IR spectra of H1245 imidazole crystals and of D1H245, D1245 and H1D245 imidazole deuterium derivative crystals. The spectra were measured using polarized light at the room temperature and at 77 K by a transmission method, for two different crystalline faces. Theoretical analysis of the results concerned linear dichroic effects, H/D isotopic and temperature effects, observed in the spectra of the hydrogen and of the deuterium bonds in imidazole crystals, at the frequency ranges of ν N–H and ν N–D bands. The basic crystal spectral properties can be satisfactorily interpreted in a quantitative way for a hydrogen bond linear dimer model. Such a model explains not only a two-branch structure of the ν N–H and ν N–D bands in crystalline spectra, but also some essential linear dichroic effects in the band frequency ranges, for isotopically diluted crystals. Model calculations, performed within the limits of the strong-coupling model, allowed for quantitative interpretation and for understanding of the basic properties of the hydrogen bond IR spectra of imidazole crystals, H/D isotopic, temperature and dichroic effects included. The results allowed verification of theoretical models proposed recently for the imidazole crystal spectra generation mechanisms. In the scope of our studies, the mechanism of H/D isotopic self-organization processes, taking place in the crystal hydrogen bond lattices, was also recognized. It was proved that for isotopically diluted crystalline samples of imidazole, a non-random distribution of protons and deuterons exclusively occurs in some restricted fragments (domains) of open chains of the hydrogen-bonded molecules. Nevertheless, these co-operative interactions between the hydrogen bonds do not concern adjacent fragments of neighboring hydrogen bond chains in the lattice. Analysis of the isotopic self-organization effects in the spectra of imidazole crystals delivered crucial arguments for understanding of the nature of the hydrogen bond spectra generation mechanisms.

Study of hydrogen bond polarized IR spectra of cinnamic acid crystals

This paper presents the results of investigation of the polarized IR spectra of cinnamic acid and of its deuterium derivative crystals. The spectra were measured by a transmission method, using polarized light, at the room temperature and at 77 K, for two different crystalline faces. Theoretical analysis of the results concerned linear dichroic effects, H/D isotopic and temperature effects, observed in the spectra of the hydrogen and of the deuterium bonds in cinnamic acid crystals, at the frequency ranges of the ν O–H and the ν O–D bands. The basic crystal spectral properties could be satisfactorily interpreted in a quantitative way for a centrosymmetric cyclic hydrogen bond dimer model. Such a model explains not only a two-branch structure of the ν O–H and ν O–D bands in crystalline spectra, but also some essential linear dichroic effects in the band frequency ranges, measured for isotopically diluted crystals. Model calculations, performed within the limits of the ‘strong-coupling’ model, allowed for quantitative interpretation and for understanding of the basic properties of the hydrogen bond IR spectra of cinnamic acid crystals, H/D isotopic, temperature and dichroic effects included. In the scope of our studies the mechanism of H/D isotopic ‘self-organization’ processes, taking place in the crystal hydrogen bond lattices, was also recognized. It was proved that for isotopically diluted crystalline samples of cinnamic acid, a non-random distribution of protons and deuterons occurs exclusively in the hydrogen bond dimers. Nevertheless, these co-operative interactions between the hydrogen bonds do not involve the adjacent hydrogen bond dimers in each unit cell. The two-branch fine structure pattern of the ν O–H and ν O–D bands was ascribed to the vibronic mechanism of vibrational dipole selection rule breaking in centrosymmetric hydrogen bond dimers. The observed in the spectra very high intensity of the forbidden transition sub-band in the analyzed ν O–H and ν O–D bands is a manifestation of an extremely effective symmetry rule breaking mechanism. It correlates with a relatively large excess electron charge on the cinnamic aid dimer carboxyl groups. This effect is a result of a partial withdrawal of the electron charge, from the conjugated π-bond systems of the styryl substituents, by the carboxyl groups. This statement has been supported by ab initio calculations.

Crystal structure and thermal desorption properties of HoNiAlD1.2

The intermetallic compound HoNiAl with the hexagonal ZrNiAl-type structure absorbs deuterium up to HoNiAlD1.3±0.1 under a D2 pressure of 3–5bar at room temperature. HoNiAlD1.20(1) has been studied by powder neutron diffraction (PND). The unit cell of the hydride is orthorhombically distorted (space group Amm2) with unit cell dimensions a(∼chex)=3.7016(2)Å, b(∼ahex√3)=12.379(1)Å and c(∼ahex)=7.6288(4)Å (b/c=0.937√3) as determined from a Rietveld refinement of high-resolution powder neutron diffraction data. The deuterium atoms fill completely the trigonal bipyramid Ho3Ni2 and the most expanded of six chemically equivalent and crystallographically different Ho2NiAl tetrahedra (r=0.49Å; occupancy 81±1%). The degree of orthorhombic deformation in RENiAl-hydrides is highly dependent on the occupation of the largest RE2NiAl tetrahedron. The metal−deuterium bond distances are: Ho−D=2.16–2.44Å, Ni−D=1.61–1.85Å and Al−D=1.91Å. The shortest deuterium−deuterium interatomic distances are quite long (D−D≥2.42Å).

2H and 13C NMR investigation of deuterofullerites C60Dx

Deuterofullerites C60Dx have been studied by 2H and 13C NMR. These fullerites have two types of carbon–deuterium bonds: C–D terminal bonds, characterized by the quadrupole coupling constant (QCC) of 171 kHz, and –C ··· D ··· C– bridging bonds with a QCC of 56 kHz. The latter is responsible for the rigid lattice found in these fullerites, which is untypical of fullerenes.

A hydrogen bonded complex C2H2…HBr isolated and characterized in the gas phase using pulsed-jet, Fourier transform microwave spectroscopy

A complex formed from ethyne and hydrogen bromide has been isolated and characterized by using a fast-mixing nozzle in conjunction with a pulsed-jet, Fourier transform microwave spectrometer. Any possible chemical reaction between the two components when mixed in the usual way was thereby precluded. The rotational constants A, B and C, the quartic centrifugal distortion constants δJ, δJk and δJ and the Br nuclear hyperfine coupling constants Xaa and Xbb—Xcc (nuclear quadrupole) and Mbb (spin-rotation) were determined for each of the five isotopomers C2H2…H79Br, C2H2…H81 Br, C2H2…D79Br, C2H2…D81Br and C2D2…H79Br. Interpretations of the spectroscopic constants show that the complex is planar and T shaped in the equilibrium conformation, with HCCH internuclear axis forming the cross of the T and the HBr internuclear axis lying along the C2 axis of C2H2. The H of HBr is closer to the centre (*) of the π bond of ethyne, and therefore HBr is involved in a hydrogen bond to the π system, in which the distance of H from * is r (*…H) = 2.469(1) A. The intermolecular stretching force constant is estimated as kσ = 5.38(2) Nm−1 for the species involving a hydrogen bond (C2H2…H79Br, C2H2…H81Br and C2D2…H79Br) while this quantity increases to kσ = 5.68(2)Nm−1 for those complexes bound through a deuterium bond (C2H2…D79Br and C2H2…D79Br). The opportunity is taken to consider similarities in the properties of complexes within the two series B…HBr and B…HC1 for a range of Lewis bases B, including B = C2H2. Some family relationships are identified in the two series.

Effect of deuterium postmetal annealing on the reliability characteristics of an atomic-layer-deposited HfO2/SiO2 stack gate dielectrics

The characteristics of atomic-layer-deposited (ALD) HfO2(30 Å)/SiO2(10 Å) stacks gate dielectrics were investigated after annealing in a deuterium (D2) ambient. Compared with oxides annealed in a forming gas containing hydrogen (H2), the stack dielectrics annealed in D2 ambient exhibited various advantages such as less charge trapping, less generation of interface state density (Dit), a larger charge-to-breakdown (Qbd), and longer time-dependent dielectric breakdown characteristics under conditions of electrical stress. The improved reliability can be attributed to the strength of the deuterium bond. This deuterium postmetal annealing of a high-k gate dielectric has considerable potential for future use in ultralarge-scale integration device applications.

ChemInform Abstract: Tetragonal Structure of Neodymium Deuteride NdD2.27 Revisited.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Direct Observation of Protein Vibrations by Selective Incorporation of Spectroscopically Observable Carbon−Deuterium Bonds in Cytochrome c

ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTDirect Observation of Protein Vibrations by Selective Incorporation of Spectroscopically Observable Carbon−Deuterium Bonds in Cytochrome cJodie K. Chin, Ralph Jimenez, and Floyd E. RomesbergView Author Information Department of Chemistry, The Scripps Research Institute 10550 North Torrey Pines Road, La Jolla, California 92037 Cite this: J. Am. Chem. Soc. 2001, 123, 10, 2426–2427Publication Date (Web):February 16, 2001Publication History Received14 September 2000Published online16 February 2001Published inissue 1 March 2001https://doi.org/10.1021/ja0033741Copyright © 2001 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views615Altmetric-Citations76LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (28 KB) Get e-AlertsSupporting Info (1)»Supporting Information Supporting Information SUBJECTS:Bioinorganic chemistry,Ligands,Oscillation,Peptides and proteins,Redox reactions Get e-Alerts

Suppression of microtubule dynamic instability and treadmilling by deuterium oxide.

Deuterium oxide (D(2)O) is known to promote the assembly of tubulin into microtubules in vitro, to increase the volume of mitotic spindles and the number and length of spindle microtubules, and to inhibit mitosis. Reasoning that its actions on cellular microtubules could be due to modulation of microtubule dynamics, we examined the effects of replacing H(2)O with D(2)O on microtubule dynamic instability, treadmilling, and steady-state GTPase activity. We found that replacing 50% or more of the H(2)O with D(2)O promoted microtubule polymerization and stabilized microtubules against dilution-induced disassembly. Using steady-state axoneme-seeded microtubules composed of pure tubulin and video microscopy, we found that 84% D(2)O decreased the catastrophe frequency by 89%, the shortening rate by 80%, the growing rate by 50%, and the dynamicity by 93%. Sixty percent D(2)O decreased the treadmilling rate of microtubules composed of tubulin and microtubule-associated proteins by 42%, and 89% D(2)O decreased the steady-state GTP hydrolysis rate by 90%. The mechanism responsible for the ability of D(2)O to stabilize microtubule dynamics may involve enhancement of hydrophobic interactions in the microtubule lattice and/or the substitution of deuterium bonds for hydrogen bonds.

Incoherent elastic-neutron-scattering study of the vibrational dynamics and spin-related symmetry of protons in theKHCO3crystal

The potassium hydrogen carbonate crystal $({\mathrm{KHCO}}_{3})$ and its deuterated analog $({\mathrm{KDCO}}_{3})$ contain centrosymmetric dimer entities $({\mathrm{HCO}}_{3}^{\mathrm{\ensuremath{-}}}{)}_{2},$ or $({\mathrm{DCO}}_{3}^{\mathrm{\ensuremath{-}}}{)}_{2},$ linked by moderately strong hydrogen or deuterium bonds. The OH/OD bonds are virtually parallel to each other throughout the crystal. The incoherent elastic-neutron-scattering functions (IENSF) ${S(Q}_{x}{,Q}_{y}{,Q}_{z}=0,\ensuremath{\omega}=0)$ and ${S(Q}_{x}{,Q}_{y}=0,{Q}_{z},\ensuremath{\omega}=0)$ were measured over the momentum transfer range from \ensuremath{\sim}0 to \ensuremath{\sim}30 ${\mathrm{\AA{}}}^{\mathrm{\ensuremath{-}}1}$, with resolution of $\ensuremath{\Delta}|\mathbf{Q}|\ensuremath{\sim}1{\AA{}}^{\ensuremath{-}1}.$ The components of the momentum transfer ${Q}_{x},$ ${Q}_{y},$ and ${Q}_{z}$ were parallel to the mean directions of the stretching, in-plane, and out-of-plane bending modes of protons or deuterons, respectively. For ${\mathrm{KHCO}}_{3},$ the broad incoherent scattering peaks, centered at $\mathbf{Q}=0,$ are not amenable to the IENSF calculated with various models: the single harmonic oscillator, the double minimum potential, and the pair of coupled harmonic oscillators. Then, the degenerate ground state of a pair of coupled protons is regarded as composed of indistinguishable fermions. According to the Pauli principle, the symmetric and antisymmetric coordinates are singlet and triplet states, respectively. The IENSF gives quantum interferences that compare favorably to the observations. The estimated mean-square amplitudes in the ground state are amenable to isolated harmonic proton oscillators. Incoherent scattering for ${\mathrm{KDCO}}_{3}$ is amenable to Gaussian profiles for bosons. There is no evidence for quantum interference. The profile narrowing reveals an increase of the mean-square amplitudes attributed to a rather large coupling of the deuteron dynamics to the crystal lattice.

The molecular complexes of deoxycholic acid and cholesterol with CH3COOD studied by infrared spectroscopy

The frequencies of the O-D stretching vibrations of CH3COOD have been measured in the liquid and vapour phases and in the form of molecular associations with deoxycholic acid and cholesterol. The spectra confirm that the vapour phase is a mixture of monomeric and dimeric forms at room temperature. The vibrational assignment made for the gaseous phase is used in conjunction with prior data available on the monomeric O-D stretching frequencies in solutions to explain the spectroscopic behaviour of the molecular complexes. The pattern of frequency shifts suggests that deuterium bonding links the cholesterol and CH3COOD in the hydrophilic regions and that the self association of the heavy acid is limited to the dimeric species in the complex with deoxycholic acid. Extra absorption bands observed in the spectral region characteristic of the deuterium bond vibrations are tentatively considered to arise from O-D groups in different local environments with different vibrational energies compared with the D-bonded species. Further evidence for steroid-CH3COOD interactions is obtained from a study of the O-H and CbetaO stretching vibrations of the compounds.Key words: acetic acid-d, complexation with deoxycholic acid and cholesterol, infrared spectroscopy.