The Weak Visible n → π* Transition of CF3NO: Vertical Accuracy versus Spectral Agreement
- 1Universidade Federal Rural do Rio de Janeiro (UFRRJ) , , BR-465, Km 07 , ,
- 2Universidade Federal Fluminense , , Outeiro de S. João Batista s/n , Centro, , ,
Abstract
Trifluoronitrosomethane (CF3NO), one of the few relatively stable blue gases, owes its color to a weak, structured n → π* absorption near 690 nm. Its small size suggests a straightforward benchmark, yet vertical excited-state methods place this transition very differently. We investigate this discrepancy by treating the vertical excitation, the 0–0 transition, and the finite-temperature band envelope as distinct observables. The benchmark combines full linear-response TD-DFT and TDA for five functionals with EOM-CCSD and EOM-CC3 vertical references, together with CCSD(T), CASSCF/NEVPT2, spin–orbit, structural, and vibronic analyses. At the reference geometry, S0 is predominantly closed-shell, whereas S1 is an isolated, spin-pure state dominated by n(N) → π*(N═O); these diagnostics argue against pronounced multireference character, ambiguous state identity, or appreciable spin–orbit mixing as dominant explanations of the method dependence at the reference structure. EOM-CC3/aug-cc-pVTZ gives 1.974 eV, and EOM-CCSD lies only about 0.03 eV higher. Full LR-TDDFT is 0.142–0.231 eV lower (red-shifted), whereas TDA raises the same state by 0.102–0.179 eV and brings every tested functional closer to the coupled-cluster reference. The jet-cooled 0–0 origin (1.727 eV) and strongest room-temperature feature (1.789 eV) lie well below the vertical region. The local harmonic vibronic models also underestimate the 0–0 energy and recover the gross experimental envelope only after empirical alignment and broadening. CF3NO therefore provides a compact benchmark in which vertical accuracy, state character, and spectral agreement can be separated quantitatively rather than collapsed into a single comparison.
Related
- Vivaray Hb pro non-invasive hemoglobin device: A prospective diagnostic accuracy study measuring agreement with a calibrated blood cell counter
- Transition from buoyancy-driven to shear-driven melting in a buoyant plume at a vertical ice face
- Transition to turbulence in swirl created by a vertical magnetic field in liquid metal electrodes
- Spectral properties of orthorhombic KSbOSiO4 crystals: studies of infrared, visible and ultraviolet radiation absorption, Raman scattering, cathodoluminescence and photoluminescence
- Universality in the Transition from Inspiral to Plunge for Extreme-Mass-Ratio-Inspirals: High-Accuracy Analytic Solutions and Catastrophe Theory
BibTeX
@article{hage2026weak,
title = {{The Weak Visible n → π* Transition of CF3NO: Vertical Accuracy versus Spectral Agreement}},
author = {Gabrielly da S. Hage and Pedro Henrique R. de Oliveira and Glaucio B. Ferreira and Henrique C. Silva Junior},
journal = {ACS Omega},
year = {2026},
month = oct,
doi = {10.1021/acsomega.6c11480},
url = {https://pubs.acs.org/acsodf/article/11/41/64274/5447592/The-Weak-Visible-n-Transition-of-CF3NO-Vertical},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - The Weak Visible n → π* Transition of CF3NO: Vertical Accuracy versus Spectral Agreement
AU - Gabrielly da S. Hage
AU - Pedro Henrique R. de Oliveira
AU - Glaucio B. Ferreira
AU - Henrique C. Silva Junior
PY - 2026
DA - 2026/10/09
JO - ACS Omega
DO - 10.1021/acsomega.6c11480
UR - https://pubs.acs.org/acsodf/article/11/41/64274/5447592/The-Weak-Visible-n-Transition-of-CF3NO-Vertical
AB - Trifluoronitrosomethane (CF3NO), one of the few relatively stable blue gases, owes its color to a weak, structured n → π* absorption near 690 nm. Its small size suggests a straightforward benchmark, yet vertical excited-state methods place this transition very differently. We investigate this discrepancy by treating the vertical excitation, the 0–0 transition, and the finite-temperature band envelope as distinct observables. The benchmark combines full linear-response TD-DFT and TDA for five functionals with EOM-CCSD and EOM-CC3 vertical references, together with CCSD(T), CASSCF/NEVPT2, spin–orbit, structural, and vibronic analyses. At the reference geometry, S0 is predominantly closed-shell, whereas S1 is an isolated, spin-pure state dominated by n(N) → π*(N═O); these diagnostics argue against pronounced multireference character, ambiguous state identity, or appreciable spin–orbit mixing as dominant explanations of the method dependence at the reference structure. EOM-CC3/aug-cc-pVTZ gives 1.974 eV, and EOM-CCSD lies only about 0.03 eV higher. Full LR-TDDFT is 0.142–0.231 eV lower (red-shifted), whereas TDA raises the same state by 0.102–0.179 eV and brings every tested functional closer to the coupled-cluster reference. The jet-cooled 0–0 origin (1.727 eV) and strongest room-temperature feature (1.789 eV) lie well below the vertical region. The local harmonic vibronic models also underestimate the 0–0 energy and recover the gross experimental envelope only after empirical alignment and broadening. CF3NO therefore provides a compact benchmark in which vertical accuracy, state character, and spectral agreement can be separated quantitatively rather than collapsed into a single comparison.
SN - 2470-1343
ER -