Diethyl sulfide

Data at NIST subscription sites:

NIST subscription sites provide data under the NIST Standard Reference Data Program, but require an annual fee to access. The purpose of the fee is to recover costs associated with the development of data collections included in such sites. Your institution may already be a subscriber. Follow the links above to find out more about the data in these sites and their terms of usage.


Gas phase thermochemistry data

Go To: Top, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein

Quantity Value Units Method Reference Comment
Δfgas-83.5 ± 2.3kJ/molCcbVoronkov, Klyuchnikov, et al., 1989 
Δfgas-82.72 ± 0.79kJ/molCcrHubbard, Good, et al., 1958see Hubbard, Katz, et al., 1954

Condensed phase thermochemistry data

Go To: Top, Gas phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Δfliquid-119.3 ± 2.0kJ/molCcbVoronkov, Klyuchnikov, et al., 1989ALS
Δfliquid-119.4 ± 0.84kJ/molCcrHubbard, Good, et al., 1958Reanalyzed by Cox and Pilcher, 1970, Original value = -118.6 ± 0.79 kJ/mol; see Hubbard, Katz, et al., 1954; ALS
Quantity Value Units Method Reference Comment
Δcliquid-3486.1 ± 0.67kJ/molCcrHubbard, Good, et al., 1958Reanalyzed by Cox and Pilcher, 1970, Original value = -3485.4 ± 0.67 kJ/mol; see Hubbard, Katz, et al., 1954; ALS
Δcliquid-3471.kJ/molCcbBerthelot, 1901ALS
Quantity Value Units Method Reference Comment
liquid269.28J/mol*KN/AScott, Finke, et al., 1952DH

Constant pressure heat capacity of liquid

Cp,liquid (J/mol*K) Temperature (K) Reference Comment
171.42298.15Scott, Finke, et al., 1952T = 16 to 316 K.; DH

Phase change data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled as indicated in comments:
BS - Robert L. Brown and Stephen E. Stein
TRC - Thermodynamics Research Center, NIST Boulder Laboratories, Chris Muzny director
AC - William E. Acree, Jr., James S. Chickos
ALS - Hussein Y. Afeefy, Joel F. Liebman, and Stephen E. Stein
DRB - Donald R. Burgess, Jr.
DH - Eugene S. Domalski and Elizabeth D. Hearing

Quantity Value Units Method Reference Comment
Tboil365. ± 1.KAVGN/AAverage of 12 values; Individual data points
Quantity Value Units Method Reference Comment
Tfus169.85KN/ATimmermans, 1952Uncertainty assigned by TRC = 0.6 K; TRC
Tfus169.24KN/AMcallan, Cullum, et al., 1951Uncertainty assigned by TRC = 0.1 K; TRC
Tfus169.85KN/ATimmermans and Hennaut-Roland, 1935Uncertainty assigned by TRC = 0.4 K; TRC
Quantity Value Units Method Reference Comment
Ttriple169.21KN/AScott, Finke, et al., 1952, 2Uncertainty assigned by TRC = 0.02 K; TRC
Quantity Value Units Method Reference Comment
Tc557.KN/AMajer and Svoboda, 1985 
Tc557.0KN/ABerthoud and Brum, 1924Uncertainty assigned by TRC = 0.5 K; by disappearance of meniscus; TRC
Quantity Value Units Method Reference Comment
Pc39.60barN/ABerthoud and Brum, 1924Uncertainty assigned by TRC = 0.4053 bar; vapor pressure at Tc; TRC
Quantity Value Units Method Reference Comment
ρc3.151mol/lN/ABerthoud and Brum, 1924Uncertainty assigned by TRC = 0.02 mol/l; TRC
Quantity Value Units Method Reference Comment
Δvap35.9 ± 0.6kJ/molAVGN/AAverage of 8 values; Individual data points

Enthalpy of vaporization

ΔvapH (kJ/mol) Temperature (K) Method Reference Comment
31.77365.3N/AMajer and Svoboda, 1985 
34.9327.N/ABaev, 2008Based on data from 293. to 361. K.; AC
34.4333.A,EBStephenson and Malanowski, 1987Based on data from 318. to 396. K. See also Scott, Finke, et al., 1952 and Osborn and Douslin, 1966.; AC
34.8324.EBWhite, Barnard--Smith, et al., 1952Based on data from 309. to 371. K.; AC
37.5248.N/AStull, 1947Based on data from 233. to 361. K.; AC
33.5364.N/AThompson and Linnett, 1935AC

Enthalpy of vaporization

ΔvapH = A exp(-βTr) (1 − Tr)β
    ΔvapH = Enthalpy of vaporization (at saturation pressure) (kJ/mol)
    Tr = reduced temperature (T / Tc)

View plot Requires a JavaScript / HTML 5 canvas capable browser.

Temperature (K) A (kJ/mol) β Tc (K) Reference Comment
325. to 365.51.830.2843557.Majer and Svoboda, 1985 

Antoine Equation Parameters

log10(P) = A − (B / (T + C))
    P = vapor pressure (bar)
    T = temperature (K)

View plot Requires a JavaScript / HTML 5 canvas capable browser.

Temperature (K) A B C Reference Comment
319.07 to 395.584.053261257.833-54.488Osborn and Douslin, 1966 
233.6 to 361.4.665831560.523-26.557Stull, 1947Coefficents calculated by NIST from author's data.
361. to 536.4.416691541.596-11.154Stull, 1947Coefficents calculated by NIST from author's data.

Enthalpy of fusion

ΔfusH (kJ/mol) Temperature (K) Reference Comment
11.903169.21Scott, Finke, et al., 1952DH
11.92169.2Domalski and Hearing, 1996AC

Entropy of fusion

ΔfusS (J/mol*K) Temperature (K) Reference Comment
70.35169.21Scott, Finke, et al., 1952DH

In addition to the Thermodynamics Research Center (TRC) data available from this site, much more physical and chemical property data is available from the following TRC products:


Reaction thermochemistry data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Michael M. Meot-Ner (Mautner) and Sharon G. Lias

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. A general reaction search form is also available. Future versions of this site may rely on reaction search pages in place of the enumerated reaction displays seen below.

Individual Reactions

C4H10S+ + Diethyl sulfide = (C4H10S+ • Diethyl sulfide)

By formula: C4H10S+ + C4H10S = (C4H10S+ • C4H10S)

Bond type: Charge transfer bond (positive ion)

Quantity Value Units Method Reference Comment
Δr104.kJ/molDTJames, McKee, et al., 1996gas phase; ΔrH(0K) = 107. kJ/mol
Δr112.kJ/molDTDeng, Illies, et al., 1995gas phase; ΔrH(0K) = 120. kJ/mol
Quantity Value Units Method Reference Comment
Δr118.J/mol*KDTJames, McKee, et al., 1996gas phase; ΔrH(0K) = 107. kJ/mol
Δr143.J/mol*KDTDeng, Illies, et al., 1995gas phase; ΔrH(0K) = 120. kJ/mol

Gas phase ion energetics data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Ion clustering data, IR Spectrum, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data evaluated as indicated in comments:
HL - Edward P. Hunter and Sharon G. Lias
L - Sharon G. Lias

Data compiled as indicated in comments:
LLK - Sharon G. Lias, Rhoda D. Levin, and Sherif A. Kafafi
RDSH - Henry M. Rosenstock, Keith Draxl, Bruce W. Steiner, and John T. Herron

Quantity Value Units Method Reference Comment
IE (evaluated)8.42 ± 0.01eVN/AN/AL
Quantity Value Units Method Reference Comment
Proton affinity (review)856.7kJ/molN/AHunter and Lias, 1998HL
Quantity Value Units Method Reference Comment
Gas basicity827.0kJ/molN/AHunter and Lias, 1998HL

Ionization energy determinations

IE (eV) Method Reference Comment
8.41CTSAloisi, Santini, et al., 1974LLK
8.42 ± 0.01PIAkopyan, Sergeev, et al., 1970RDSH
8.430 ± 0.005PIWatanabe, Nakayama, et al., 1962RDSH
8.4PEAue and Bowers, 1979Vertical value; LLK
8.46PEWeiner and Lattman, 1978Vertical value; LLK
8.44PEWagner and Bock, 1974Vertical value; LLK
8.44PEBock, Wagner, et al., 1972Vertical value; LLK

Appearance energy determinations

Ion AE (eV) Other Products MethodReferenceComment
CHS+15.3 ± 0.5?EIHobrock and Kiser, 1963RDSH
CH2S+11.75 ± 0.03C2H4+CH4PIAkopyan, Sergeev, et al., 1970RDSH
CH2S+12.5 ± 0.3?EIHobrock and Kiser, 1963RDSH
CH3S+12.00 ± 0.05C2H4+CH3PIAkopyan, Sergeev, et al., 1970RDSH
CH3S+12.3 ± 0.1?EIKeyes and Harrson, 1968RDSH
C2H2+21.7 ± 0.3?EIGal'perin, Bogolyubov, et al., 1969RDSH
C2H3+16.7 ± 0.5?EIHobrock and Kiser, 1963RDSH
C2H3S+14.6 ± 0.4?EIHobrock and Kiser, 1963RDSH
C2H4+14.5 ± 0.3?EIGal'perin, Bogolyubov, et al., 1969RDSH
C2H4S+9.9 ± 0.3C2H6PIAkopyan, Sergeev, et al., 1970RDSH
C2H4S+11.2 ± 0.2?EIHobrock and Kiser, 1963RDSH
C2H5+14.5 ± 0.3?EIHobrock and Kiser, 1963RDSH
C2H5S+10.23 ± 0.03C2H5PIAkopyan, Sergeev, et al., 1970RDSH
C2H5S+11.05C2H5EIGowenlock, Kay, et al., 1963RDSH
C2H6S+9.90 ± 0.03C2H4PIAkopyan, Sergeev, et al., 1970RDSH
C2H6S+10.4 ± 0.2?EIHobrock and Kiser, 1963RDSH
C3H5+12.41 ± 0.05CH3SH+HPIAkopyan, Sergeev, et al., 1970RDSH
C3H7S+10.7 ± 0.15CH3EIBroer and Weringa, 1980LLK
C3H7S+10.16 ± 0.05CH3PIAkopyan, Sergeev, et al., 1970RDSH
C3H7S+10.65CH3EIGowenlock, Kay, et al., 1963RDSH
C4H9S+10.2 ± 0.1HPIAkopyan, Sergeev, et al., 1970RDSH

Ion clustering data

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, IR Spectrum, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: Michael M. Meot-Ner (Mautner) and Sharon G. Lias

Note: Please consider using the reaction search for this species. This page allows searching of all reactions involving this species. Searches may be limited to ion clustering reactions. A general reaction search form is also available.

Clustering reactions

C4H10S+ + Diethyl sulfide = (C4H10S+ • Diethyl sulfide)

By formula: C4H10S+ + C4H10S = (C4H10S+ • C4H10S)

Bond type: Charge transfer bond (positive ion)

Quantity Value Units Method Reference Comment
Δr104.kJ/molDTJames, McKee, et al., 1996gas phase; ΔrH(0K) = 107. kJ/mol
Δr112.kJ/molDTDeng, Illies, et al., 1995gas phase; ΔrH(0K) = 120. kJ/mol
Quantity Value Units Method Reference Comment
Δr118.J/mol*KDTJames, McKee, et al., 1996gas phase; ΔrH(0K) = 107. kJ/mol
Δr143.J/mol*KDTDeng, Illies, et al., 1995gas phase; ΔrH(0K) = 120. kJ/mol

IR Spectrum

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, References, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Data compiled by: NIST Mass Spectrometry Data Center, William E. Wallace, director

Gas Phase Spectrum

Notice: This spectrum may be better viewed with a Javascript and HTML 5 enabled browser.

IR spectrum
For Zoom
1.) Enter the desired X axis range (e.g., 100, 200)
2.) Check here for automatic Y scaling
3.) Press here to zoom

Notice: Concentration information is not available for this spectrum and, therefore, molar absorptivity values cannot be derived.

Additional Data

View image of digitized spectrum (can be printed in landscape orientation).

View spectrum image in SVG format.

Download spectrum in JCAMP-DX format.

Owner NIST Standard Reference Data Program
Collection (C) 2018 copyright by the U.S. Secretary of Commerce
on behalf of the United States of America. All rights reserved.
Origin NIST Mass Spectrometry Data Center
State gas
Instrument HP-GC/MS/IRD

This IR spectrum is from the NIST/EPA Gas-Phase Infrared Database .


References

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, Notes

Data compilation copyright by the U.S. Secretary of Commerce on behalf of the U.S.A. All rights reserved.

Voronkov, Klyuchnikov, et al., 1989
Voronkov, M.G.; Klyuchnikov, V.A.; Kolabin, S.N.; Shvets, G.N.; Varusin, P.I.; Deryagina, E.N.; Korchevin, N.A.; Tsvetnitskaya, S.I., Thermochemical properties of diorganyl chalcogenides and dichalcogenides RMnR(M = S, Se, Te; n = 1, 2)., Dokl. Phys. Chem. (Engl. Transl.), 1989, 307, 650-653, In original 1139. [all data]

Hubbard, Good, et al., 1958
Hubbard, W.N.; Good, W.D.; Waddington, G., The heats of combustion, formation and isomerization of the seven isomeric C4H10S alkane thiols and sulfides, J. Phys. Chem., 1958, 62, 614-617. [all data]

Hubbard, Katz, et al., 1954
Hubbard, W.N.; Katz, C.; Waddington, G., A rotating combustion bomb for precision calorimetry. Heats of combustion of some sulfur-containing compounds, J. Phys. Chem., 1954, 58, 142. [all data]

Cox and Pilcher, 1970
Cox, J.D.; Pilcher, G., Thermochemistry of Organic and Organometallic Compounds, Academic Press, New York, 1970, 1-636. [all data]

Berthelot, 1901
Berthelot, M., Chimie Organique. - Nouvelles recherches sur l'isomerie des ethers sulfocyaniques, Compt. Rend., 1901, 132, 57-58. [all data]

Scott, Finke, et al., 1952
Scott, D.W.; Finke, H.L.; Hubbard, W.N.; McCullough, J.P.; Oliver, G.D.; Gross, M.E.; Katz, C.; Williamson, K.D.; Waddington, G.; Huffman, H.M., 3-Thiapentane: heat capacity, heats of fusion and vaporization, vapor pressure, entropy, heat of formation and thermodynamic functions, J. Am. Chem. Soc., 1952, 74, 4656-4662. [all data]

Timmermans, 1952
Timmermans, J., Freezing points of organic compounds. VVI New determinations., Bull. Soc. Chim. Belg., 1952, 61, 393. [all data]

Mcallan, Cullum, et al., 1951
Mcallan, D.T.; Cullum, T.V.; Dean, R.A.; Fidler, F.A., The Preparation and Properties of Sulfur Compounds Related to Petroleum I. The Dialkyl Sulfides and Disulfides, J. Am. Chem. Soc., 1951, 73, 3627-32. [all data]

Timmermans and Hennaut-Roland, 1935
Timmermans, J.; Hennaut-Roland, M., Physical constants of 20 organic compounds. VII., J. Chim. Phys. Phys.-Chim. Biol., 1935, 32, 501. [all data]

Scott, Finke, et al., 1952, 2
Scott, D.W.; Finke, H.L.; Hubbard, W.N.; McCullough, J.P.; Oliver, G.D.; Gross, M.E.; Katz, C.; Williamson, K.D.; Waddington, G.; Huffman, H.M., 3-Thiapentane: Heat Capacity, Heats of Fusion and Vaporization, Vapor Pressure, Entropy, Heat of Formation and Thermodynamic Functions, J. Am. Chem. Soc., 1952, 74, 4656-62. [all data]

Majer and Svoboda, 1985
Majer, V.; Svoboda, V., Enthalpies of Vaporization of Organic Compounds: A Critical Review and Data Compilation, Blackwell Scientific Publications, Oxford, 1985, 300. [all data]

Berthoud and Brum, 1924
Berthoud, A.; Brum, R., Physical Properties of Some Organic Compounds., J. Chim. Phys. Phys.-Chim. Biol., 1924, 21, 143-60. [all data]

Baev, 2008
Baev, A.K., The thermodynamic characteristics of diethylzinc-diethylsulfur solutions, Russ. J. Phys. Chem. A, 2008, 82, 8, 1266-1272, https://doi.org/10.1134/S0036024408080050 . [all data]

Stephenson and Malanowski, 1987
Stephenson, Richard M.; Malanowski, Stanislaw, Handbook of the Thermodynamics of Organic Compounds, 1987, https://doi.org/10.1007/978-94-009-3173-2 . [all data]

Osborn and Douslin, 1966
Osborn, A.G.; Douslin, D.R., Vapor Pressure Relations of 36 Sulfur Compounds Present in Petroleum., J. Chem. Eng. Data, 1966, 11, 4, 502-509, https://doi.org/10.1021/je60031a014 . [all data]

White, Barnard--Smith, et al., 1952
White, P.T.; Barnard--Smith, D.G.; Fidler, F.A., Vapor Pressure--Temperature Relationships of Sulfur Compounds Related to Petroleum, Ind. Eng. Chem., 1952, 44, 6, 1430-1438, https://doi.org/10.1021/ie50510a064 . [all data]

Stull, 1947
Stull, Daniel R., Vapor Pressure of Pure Substances. Organic and Inorganic Compounds, Ind. Eng. Chem., 1947, 39, 4, 517-540, https://doi.org/10.1021/ie50448a022 . [all data]

Thompson and Linnett, 1935
Thompson, H.W.; Linnett, J.W., The vapour pressures of some alkyl sulphides, Trans. Faraday Soc., 1935, 31, 1743, https://doi.org/10.1039/tf9353101743 . [all data]

Domalski and Hearing, 1996
Domalski, Eugene S.; Hearing, Elizabeth D., Heat Capacities and Entropies of Organic Compounds in the Condensed Phase. Volume III, J. Phys. Chem. Ref. Data, 1996, 25, 1, 1, https://doi.org/10.1063/1.555985 . [all data]

James, McKee, et al., 1996
James, M.A.; McKee, M.L.; Illies, A.J., Gas-phase bond strength and atomic connectivity studies of the unsymmetrical two-center three-electron ion, [Et2S...SMe2]+, J. Am. Chem. Soc., 1996, 118, 33, 7836, https://doi.org/10.1021/ja960455h . [all data]

Deng, Illies, et al., 1995
Deng, Y.; Illies, A.J.; James, M.A.; McKee, M.L.; Peschke, M., A Definitive Investigation of the Gas-Phase Two-Center Three-electron Bond in [H2S:SH2+], [Me2S:SMe2]+, and [Et2S:SEt2]+: Therory and Experiment, J. Am. Chem. Soc., 1995, 117, 1, 420, https://doi.org/10.1021/ja00106a048 . [all data]

Hunter and Lias, 1998
Hunter, E.P.; Lias, S.G., Evaluated Gas Phase Basicities and Proton Affinities of Molecules: An Update, J. Phys. Chem. Ref. Data, 1998, 27, 3, 413-656, https://doi.org/10.1063/1.556018 . [all data]

Aloisi, Santini, et al., 1974
Aloisi, G.G.; Santini, S.; Sorriso, S., Molecular complexes of substituted diphenyl sulphides with π acceptors. Charge transfer spectra and ionization potentials of the donors, J. Chem. Soc. Faraday Trans. 1, 1974, 70, 1908. [all data]

Akopyan, Sergeev, et al., 1970
Akopyan, M.E.; Sergeev, Yu.L.; Vilesov, F.I., Photionization in vapors of aliphatic sulfides. I. Methymercaptan, dimethyl and diethyl sulfides, High Energy Chem., 1970, 4, 265, In original 305. [all data]

Watanabe, Nakayama, et al., 1962
Watanabe, K.; Nakayama, T.; Mottl, J., Ionization potentials of some molecules, J. Quant. Spectry. Radiative Transfer, 1962, 2, 369. [all data]

Aue and Bowers, 1979
Aue, D.H.; Bowers, M.T., Chapter 9. Stabilities of positive ions from equilibrium gas phase basicity measurements in Ions Chemistry,, ed. M.T. Bowers, 1979. [all data]

Weiner and Lattman, 1978
Weiner, M.A.; Lattman, M., Ultraviolet photoelectron spectra of some Cr(CO)5L complexes containing organosulfide and organophosphine ligands, Inorg. Chem., 1978, 17, 1084. [all data]

Wagner and Bock, 1974
Wagner, G.; Bock, H., Photoelektronenspektren und molekuleigenschaften, XXVI. Die delokalisation von schwefel-elektronenpaaren in alkylsulfiden und -disulfiden, Chem. Ber., 1974, 107, 68. [all data]

Bock, Wagner, et al., 1972
Bock, H.; Wagner, G.; Kroner, J., Photoelektronenspektren und molekuleigenschaften, XIV. Die delokalisation des schwefel-elektronenpaar in CH3S-substituierten aromaten, Chem. Ber., 1972, 105, 3850. [all data]

Hobrock and Kiser, 1963
Hobrock, B.G.; Kiser, R.W., Electron impact investigations of sulfur compounds. III. 2-Thiapropane, 3-thiapentane, and 2,3,4-trithiapentane, J. Phys. Chem., 1963, 67, 1283. [all data]

Keyes and Harrson, 1968
Keyes, B.G.; Harrson, A.G., The fragmentation of aliphatic sulfur compounds by electron impact, J. Am. Chem. Soc., 1968, 90, 5671. [all data]

Gal'perin, Bogolyubov, et al., 1969
Gal'perin, Ya.V.; Bogolyubov, G.M.; Grishin, N.N.; Petrov, A.A., Organic derivatives of elements of groups V and VI. VI. Mass spectra of compounds with S-S bonds, Zh. Obshch. Khim., 1969, 39, 1599, In original 1567. [all data]

Gowenlock, Kay, et al., 1963
Gowenlock, B.G.; Kay, J.; Majer, J.R., Electron impact studies of some sulphides and disulphides, J. Chem. Soc. Faraday Trans., 1963, 59, 2463. [all data]

Broer and Weringa, 1980
Broer, W.J.; Weringa, W.D., Potential energy profiles for the unimolecular reactions of [C3H7S]+ ions, Org. Mass Spectrom., 1980, 15, 229. [all data]


Notes

Go To: Top, Gas phase thermochemistry data, Condensed phase thermochemistry data, Phase change data, Reaction thermochemistry data, Gas phase ion energetics data, Ion clustering data, IR Spectrum, References