Infrared absorption of methanol-water clusters (CH3OH)n(H2O), n = 1-4, recorded with the VUV-ionization/IR-depletion techniques
Yu-Fang Lee,1 Anne-Marie Kelterer,2, a) Gergely Matisz,3,4 Sándor Kunsági-Máté,3,4 Chao-Yu Chung,1 and Yuan-Pern Lee1, 5, a)
1Department of Applied Chemistry and Institute of Molecular Science, National Chiao Tung University, Hsinchu 30010, Taiwan
2Institute of Physical and Theoretical Chemistry, NAWI Graz, Graz University of Technology, Stremayrgasse 9/I, A-8010 Graz, Austria
3Department of General and Physical Chemistry, University of Pécs, Ifjúság 6, H-7624 Pécs, Hungary
4János Szentágothai Research Center, Ifjúság 20, H-7624 Pécs, Hungary
5Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, Taiwan
(Received xx xxxx 2016; accepted xx xxxx 2017)
a) Authors to whom correspondence should be addressed; electronic mails: (AMK); (YPL).
Relaxed binding energies, cooperativity energies, and dissociation energies predicted for chain or branched clusters with the M06-2X/aug-cc-pVTZ method are shown in Table SI. Comparison of experimental and calculated vibrational wavenumbers and IR intensities in the OH-stretching region of trimers and tetramers other than those listed in Table II is shown in Table SII; comparison of those of pentamers other than those listed in Table II is shown in Table SIII.
Geometries and relative binding energies of WM, MW, c-M2W-dd, c-M2W-ud, c-M3W-dud, c-M3W-dda, and c-M4W-dudu predicted with the M06-2X/aug-cc-pVTZ method are shown in Fig. S1; those of WMM, MMW, MWM-da, MWM-du, c-M2W-ud-Mw, and c-M2W-ad-Mw are shown in Fig. S2. Those of c-M3W-udd-Mw, c-M3W-dud-Mw, c-M3W-dua-Ma, c-M3W-dud-Md, c-M3W-dud-Mw, M2WM2-dddd, and M2WM2-dddu are shown in Fig. S3; those of c-M2, c-M3, c-M4, and c-M5 are shown in Fig. S4.
Action spectra of a jet-cooled cluster beam of MnW produced under experimental condition A (a) and experimental condition B (b) are shown in Fig. S5. Infrared spectra of (M-W), M2W, and M3W derived from action spectra obtained in condition A and condition B according to the dissociation and ionization mechanisms described in the text are shown in Fig. S6.
TABLE SI. Binding energies, cooperativity energies, and dissociation energies (all in kJ mol−1) predicted for chain or branched clusters with the M06-2X/aug-cc-pVTZ method. Energies include BSSE and zero-point corrections and refer to relaxed monomers.
Molecule / Structure / Figure / −Ebind / −Ecoopa / E(−W) b / E(−M) bWMM / Cyclic, CH×××O bond / S2(a) / 45.1 / 6.5 / 26.1 / 28.3c
MMW / chain / S2(b) / 38.6 / 3.4 / 19.6 / 24.4c
MWM-da / chain / S2(c) / 39.0 / 4.5 / c / 24.8/22.9c
MWM-du / chain / S2(d) / 36.2 / 4.7 / c / 21.9/20.0c
c-M2W-ud-Mw / branched / S2(e) / 75.8 / 13.2 / -- / 21.0d
c-M2W-ad-Mw / branched / S2(f) / 73.8 / 11.6 / -- / 17.5d
c-M3W-udd-Mw / branched / S3(a) / 124.0 / 30.4 / (19.9)d / 24.5d
c-M3W-dud-Mw / branched / S3(b) / 121.7 / 33.6 / -- / 22.2d
c-M3W-dua-Ma / branched / S3(c) / 121.3 / 28.2 / -- / 20.2d
c-M3W-dud-Md / branched / S3(d) / 119.4 / 28.9 / -- / 19.7d
c-M3W-dud-Mw / branched / S3(e) / 119.2 / 32.7 / -- / 18.1d
M2WM2-dddd / butterfly / S3(f) / 110.8 / 19.6 / -- / --
M2WM2-dddu / butterfly / S3(g) / 110.9 / 20.4 / -- / --
a Binding energies and dissociation energies E(−W) and E(−M) are BSSE and zero-point corrected and refer to relaxed monomers and relaxed fragments.
b Ecoop includes BSSE correction at the cluster basis according to ref. [15].
c Dissociation energies are only given for outer molecules of linear chains, because the relaxed fragments for the central molecule no.2 are unambiguous.
d Dissociation energies are given only for the branched methanol molecule because of ambiguous fragments.
TABLE SII. Calculated vibrational wavenumbers (in cm-1) and IR intensities in the OH-stretching region of trimers and tetramers other than those listed in Tables II and III.
Molecule / Harmonic / Int. / Scaledcm-1 / km mol−1 / cm-1
WMM / 3939 / 88 / 3722
3906 / 60 / 3691
3725 / 414 / 3520
3629 / 479 / 3429
MMW / 3960 / 113 / 3742
3860 / 14 / 3647
3757 / 289 / 3550
3722 / 800 / 3517
MWM-da / 3937 / 112 / 3720
3899 / 64 / 3684
3775 / 342 / 3567
3676 / 428 / 3473
MWM-du / 3901 / 64 / 3686
3869 / 117 / 3656
3752 / 340 / 3545
3655 / 817 / 3454
c-M2W-ud-Mw / 3902 / 63 / 3687
3779 / 437 / 3570
3723 / 330 / 3518
3702 / 367 / 3498
3533 / 508 / 3338
c-M2W-ad-Mw / 3903 / 57 / 3688
3785 / 830 / 3576
3719 / 81 / 3515
3650 / 880 / 3449
3595 / 302 / 3397
TABLE SIII. Calculated vibrational wavenumbers (in cm-1) and IR intensities in the OH-stretching region of pentamers other than those listed in Table III.
cm-1 / km mol−1 / cm-1
c-M3W-udd-Mw / 3793 / 315 / 3584
3771 / 176 / 3563
3556 / 686 / 3360
3497 / 1158 / 3304
3467 / 424 / 3276
3249 / 827 / 3070
c-M3W-dud-Mw / 3921 / 81 / 3705
3809 / 249 / 3599
3595 / 628 / 3397
3511 / 1144 / 3318
3441 / 908 / 3251
3160 / 769 / 2986
c-M3W-dua-Ma / 3932 / 81 / 3715
3754 / 571 / 3547
3711 / 294 / 3507
3667 / 499 / 3456
3436 / 828 / 3247
3277 / 988 / 3096
c-M3W-dud-Md / 3933 / 95 / 3716
3790 / 240 / 3581
3604 / 523 / 3405
3529 / 1290 / 3335
3519 / 1012 / 3325
3414 / 358 / 3226
c-M3W-dud-Mw / 3890 / 53 / 3676
3758 / 361 / 3551
3567 / 576 / 3370
3452 / 1107 / 3262
3432 / 2015 / 3243
3332 / 297 / 3148
M2WM2-dddd / 3731 / 211 / 3525
3724 / 1120 / 3519
3706 / 587 / 3502
3679 / 723 / 3476
3654 / 165 / 3453
3625 / 14 / 3425
M2WM2-dddu / 3718 / 112 / 3513
3704 / 859 / 3500
3690 / 1583 / 3487
3679 / 441 / 3476
3641 / 170 / 3440
3600 / 61 / 3402
Fig. S1 Geometries and relative binding energies (in kJ mol−1, BSSE and ZPE-corrected) of (a) WM, (b) MW, (c) c-M2W-dd, (d) c-M2W-ud, (e) c-M3W-dud, (f) c-M3W-dda, and (g) c-M4W-dudu predicted with the M06-2X/aug-cc-pVTZ method. Bond distances (blue or green) are in Å, angles (red or purple) in degrees. M: methanol; W: water; f: dihedral angle.
Fig. S2 Geometries and relative binding energies (in kJ mol−1, BSSE and ZPE-corrected) of (a) WMM, (b) MMW, (c) MWM-da, (d) MWM-du, (e) c-M2W-ud-Mw, and (f) c-M2W-ad-Mw predicted with the M06-2X/aug-cc-pVTZ method. Bond distances (blue or green) are in Å, angles (red or purple) in degrees. M: methanol; W: water; f: dihedral angle.
Fig. S3 Geometries and relative binding energies (in kJ mol−1, BSSE and ZPE-corrected) of (a) c-M3W-udd-Mw, (b) c-M3W-dud-Mw, (c) c-M3W-dua-Ma, (d) c-M3W-dud-Md, (e) c-M3W-dud-Mw, (f) M2WM2-dddd, and (g) M2WM2-dddu predicted with the M06-2X/aug-cc-pVTZ method. Bond distances (blue or green) are in Å, angles (red or purple) in degrees. M: methanol; W: water; f: dihedral angle; (m): methyl group.
Fig. S4 Geometries and relative binding energies (in kJ mol−1, BSSE and ZPE corrected) of (a) c-M2, (b) c-M3, (c) c-M4, and (d) c-M5 predicted with the M06-2X/aug-cc-pVTZ method. Bond distances (blue or green) are in Å, angles (red or purple) in degrees. M: methanol; W: water; f: dihedral angle.
Fig. S5 Action spectra of a jet-cooled cluster beam of MnW produced under experimental condition A (a) and experimental condition B (b). The action spectra of (M-W)+ and MnWH+, n = 1 and 2, were recorded on monitoring the fractional variations in intensity of the ion signal as the wavelength of the IR laser was scanned.
Fig. S6 Infrared spectra of (M-W), M2W, and M3W derived from action spectra obtained in condition A (a) and condition B (b) according to the dissociation and ionization mechanisms described in the text.
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