PMID- 33078779
OWN - NLM
STAT- PubMed-not-MEDLINE
LR  - 20201028
IS  - 1463-9084 (Electronic)
IS  - 1463-9076 (Linking)
VI  - 22
IP  - 41
DP  - 2020 Oct 28
TI  - Anharmonic coupling behind vibrational spectra of solvated ammonium: lighting up 
      overtone states by Fermi resonance through tuning solvation environments.
PG  - 24059-24069
LID - 10.1039/d0cp03519j [doi]
AB  - Studies on the vibrational spectra of various ammonium-centered clusters under 
      different solvation environments have raised interest over the last thirty years. 
      The gas-phase infrared photodissociation spectroscopy (IRPD) experiments showed 
      that these NH4+Xn clusters exhibit rich spectral features from 2600 to 3400 cm-1. 
      In this work, we have simulated the vibrational spectra and analyzed couplings 
      among vibrational quantum states in the aforementioned frequency range using ab 
      initio anharmonic algorithms. Originating from the anharmonic couplings between 
      NH stretching fundamentals and bending overtones, Fermi resonance (FR) is a 
      common feature in these spectra, and its extent is determined by the magnitude of 
      couplings and the energy matching conditions between relevant states, which are 
      governed by the proton affinity, number, and bonding configuration of the 
      solvation species. For weakly bound clusters consisting of rare gas atoms, FR is 
      insignificant but not negligible; for strongly bound clusters, such as 
      ammonium-water clusters, the hydrogen-bonded NH stretching fundamentals redshift 
      and reach a better resonance condition, and thus light up the bending overtones 
      as prominent FR bands. Our simulated spectra are in good agreement with previous 
      experimental reports of these ammonium-centered clusters and provide a better 
      understanding of the vibrational coupling behind the spectra of the NH stretching 
      region.
FAU - Lin, Chih-Kai
AU  - Lin CK
AUID- ORCID: 0000-0001-5566-6238
AD  - Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, 
      Taiwan, Republic of China. ethenel@gmail.com jlkuo@pub.iams.sinica.edu.tw.
FAU - Huang, Qian-Rui
AU  - Huang QR
AUID- ORCID: 0000-0001-5384-9241
AD  - Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, 
      Taiwan, Republic of China. ethenel@gmail.com jlkuo@pub.iams.sinica.edu.tw.
FAU - Kuo, Jer-Lai
AU  - Kuo JL
AUID- ORCID: 0000-0002-0550-0181
AD  - Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei 10617, 
      Taiwan, Republic of China. ethenel@gmail.com jlkuo@pub.iams.sinica.edu.tw.
LA  - eng
PT  - Journal Article
PL  - England
TA  - Phys Chem Chem Phys
JT  - Physical chemistry chemical physics : PCCP
JID - 100888160
SB  - IM
EDAT- 2020/10/21 06:00
MHDA- 2020/10/21 06:01
CRDT- 2020/10/20 08:38
PHST- 2020/10/21 06:00 [pubmed]
PHST- 2020/10/21 06:01 [medline]
PHST- 2020/10/20 08:38 [entrez]
AID - 10.1039/d0cp03519j [doi]
PST - ppublish
SO  - Phys Chem Chem Phys. 2020 Oct 28;22(41):24059-24069. doi: 10.1039/d0cp03519j.