scholarly journals Experimental energy levels of 12C14N through marvel analysis

2020 ◽  
Vol 499 (1) ◽  
pp. 25-39
Author(s):  
Anna-Maree Syme ◽  
Laura K McKemmish
Keyword(s):  
Experimental Data ◽  
Partition Function ◽  
Energy Level ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Line List ◽  
Level Data ◽  
Vibrational Energy Levels ◽  
Cyano Radical ◽  
Current Energy

ABSTRACT The cyano radical (CN) is a key molecule across many different factions of astronomy and chemistry. Accurate, empirical rovibronic energy levels with uncertainties are determined for eight doublet states of CN using the marvel (Measured Active Rotational-Vibrational Energy Levels) algorithm. 40 333 transitions were validated from 22 different published sources to generate 8083 spin-rovibronic energy levels. The empirical energy levels obtained from the marvel analysis are compared to current energy levels from the mollist line list. The mollist transition frequencies are updated with marvel energy level data which brings the frequencies obtained through experimental data up to 77.3 per cent from the original 11.3 per cent, with 92.6 per cent of the transitions with intensities over 10−23 cm molecule−1 at 1000 K now known from experimental data. At 2000 K, 100.0 per cent of the partition function is recovered using only marvel energy levels, while 98.2 per cent is still recovered at 5000 K.

scholarly journals Physics-Guided Curve Fitting for Potential-Energy Functions of Diatomic Molecules

2021 ◽  
Author(s):  
Karl Irikura
Keyword(s):  
Potential Energy ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Spectroscopic Constants ◽  
Energy Curve ◽  
Simple Strategy ◽  
Level Data ◽  
Vibrational Energy Levels ◽  
High Level ◽  
Fitted Function

When computing the potential-energy curve of a diatomic molecule for predictive spectroscopy, high-level calculations are usually desired. The best calculations are expensive, so few points are usually available. The points are fitted to a continuous function, such as a polynomial. Ro-vibrational energy levels are then computed using the fitted function, and spectroscopic constants extracted. However, there may be problems with overfitting, with inadequate flexibility of the fitting function, or with dependence of results upon the choice of fitting function. More fundamentally, the fitting function is selected using aesthetics or convenience, instead of physics. Here we suggest using a lower-level, high-resolution ab initio potential as a guide. Instead of fitting the sparse, high-level data directly, the energy differences between the high-level points and the guiding potential are fitted. The results are improved even with an inexpensive guiding potential. This simple strategy involves little additional effort and can be recommended for routine use. It is similar to some interpolation strategies in the literature of polyatomic molecules. When the guiding potential extends beyond the high-level data, extrapolations are also improved.

Variational Calculation of the Lower Vibrational Energy Levels of the Ammonia Molecule

1982 ◽  
Vol 37 (4) ◽  
pp. 398-400 ◽  
Author(s):  
Philippe Bopp ◽  
Don R. McLaughlin ◽  
Max Wolfsberg
Keyword(s):  
Experimental Data ◽  
Degrees Of Freedom ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Variational Calculation ◽  
Ammonia Molecule ◽  
Inversion Barrier ◽  
Barrier Potential ◽  
Vibrational Energy Levels

Abstract A variational calculation of the lower-lying vibrational energy levels of the ammonia molecule is performed, in which all six vibrational degrees of freedom are treated simultaneously. A literature potential is assumed for all non-inversion motions; a new inversion barrier potential with a barrier of 1616 cm-1 is determined by fitting experimental data.

Promoting and inhibiting tunneling via nuclear motions

2016 ◽  
Vol 18 (2) ◽  
pp. 1092-1104 ◽  
Author(s):  
Attila G. Császár ◽  
Tibor Furtenbacher
Keyword(s):  
Energy Level ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Tunneling Splittings ◽  
Vibrational Energy Levels

Accurate, experimental rotational–vibrational energy levels determined via the MARVEL algorithm and published recently for the 14NH3 molecule in J. Quant. Spectrosc. Radiat. Transfer, 2015, 116, 117–130 are analyzed to unravel the promoting and inhibiting effects of vibrations and rotations on the tunneling splittings of the corresponding symmetric (s) and antisymmetric (a) rovibrational energy level pairs.

scholarly journals A high resolution line list for AlO

2021 ◽  
Author(s):  
Charles A Bowesman ◽  
Meiyin Shuai ◽  
Sergei N Yurchenko ◽  
Jonathan Tennyson
Keyword(s):  
High Resolution ◽  
Spectroscopic Data ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Laboratory Data ◽  
High Accuracy ◽  
High Resolution Spectroscopy ◽  
Line List ◽  
Vibrational Energy Levels

Abstract Indications of aluminium monoxide in atmospheres of exoplanets are being reported. Studies using high resolution spectroscopy should allow a strong detection but require high accuracy laboratory data. A Marvel (measured active rotational-vibrational energy levels) analysis is performed for the available spectroscopic data on 27Al16O: 22 473 validated transitions are used to determine 6 485 distinct energy levels. These empirical energy levels are used to provide an improved, spectroscopically accurate version of the ExoMol ATP line list for 27Al16O; at the same time the accuracy of the line lists for the isotopically-substituted species 26Al16O, 27Al17O and 27Al18O are improved by correcting levels in line with the corrections used for 27Al16O. These line lists are available from the ExoMol database at http://www.exomol.com.

scholarly journals An update to the MARVEL data set and ExoMol line list for 12C2

2020 ◽  
Vol 497 (1) ◽  
pp. 1081-1097 ◽  
Author(s):  
Laura K McKemmish ◽  
Anna-Maree Syme ◽  
Jasmin Borsovszky ◽  
Sergei N Yurchenko ◽  
Jonathan Tennyson ◽  
...  
Keyword(s):  
Cross Correlation ◽  
Vibrational Energy ◽  
Energy Levels ◽  
Experimental Studies ◽  
Electronic States ◽  
Spectroscopic Studies ◽  
Data Set ◽  
Line List ◽  
Vibronic States ◽  
Vibrational Energy Levels

ABSTRACT The spectrum of dicarbon (C2) is important in astrophysics and for spectroscopic studies of plasmas and flames. The C2 spectrum is characterized by many band systems with new ones still being actively identified; astronomical observations involve eight of these bands. Recently, Furtenbacher et al. presented a set of 5699 empirical energy levels for 12C2, distributed among 11 electronic states and 98 vibronic bands, derived from 42 experimental studies and obtained using the MARVEL (Measured Active Rotational-Vibrational Energy Levels) procedure. Here, we add data from 13 new sources and update data from 5 sources. Many of these data sources characterize high-lying electronic states, including the newly detected 3 3Πg state. Older studies have been included following improvements in the MARVEL procedure that allow their uncertainties to be estimated. These older works in particular determine levels in the C 1Πg state, the upper state of the insufficiently characterized Deslandres–d’Azambuja (C 1Πg–A 1Πu) band. The new compilation considers a total of 31 323 transitions and derives 7047 empirical (marvel) energy levels spanning 20 electronic and 142 vibronic states. These new empirical energy levels are used here to update the 8states C2 ExoMol line list. This updated line list is highly suitable for high-resolution cross-correlation studies in astronomical spectroscopy of, for example, exoplanets, as 99.4 per cent of the transitions with intensities over 10−18 cm molecule−1 at 1000 K have frequencies determined by empirical energy levels.

Master Equation for the Dissociation of a Dilute Diatomic Gas. V. Effect of Energy-level Spacing

1971 ◽  
Vol 49 (23) ◽  
pp. 3915-3917 ◽  
Author(s):  
D. L. S. Mcelwain ◽  
H. O. Pritchard
Keyword(s):  
Energy Level ◽  
Master Equation ◽  
Temperature Coefficient ◽  
Numerical Experiments ◽  
Vibrational Energy ◽  
Transition Probabilities ◽  
Energy Levels ◽  
Level Spacing ◽  
Vibrational Energy Levels ◽  
Arrhenius Temperature

Our previous vibration–dissociation coupling calculations for H2 have been repeated for D2. Closer spacing of the vibrational energy levels in D2 leads to increased translation–vibration transition probabilities, and the effect of this is to increase the rate of recombination by the vibrational mechanism at all temperatures. These numerical experiments also clarify two other issues: (i) that the position of the bottleneck does not necessarily occur at that level above which direct collisional dissociation can take place rapidly, and (ii) that there is no simple correspondence between the position of the bottleneck and the Arrhenius temperature coefficient for dissociation.

scholarly journals Research progress in the effects of terahertz waves on biomacromolecules

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Liu Sun ◽  
Li Zhao ◽  
Rui-Yun Peng
Keyword(s):  
Vibrational Energy ◽  
Rapid Development ◽  
Energy Levels ◽  
Basic Research ◽  
Research Progress ◽  
Biological Macromolecules ◽  
Terahertz Waves ◽  
Terahertz Spectrum ◽  
Biomedical Field ◽  
Vibrational Energy Levels

AbstractWith the rapid development of terahertz technologies, basic research and applications of terahertz waves in biomedicine have attracted increasing attention. The rotation and vibrational energy levels of biomacromolecules fall in the energy range of terahertz waves; thus, terahertz waves might interact with biomacromolecules. Therefore, terahertz waves have been widely applied to explore features of the terahertz spectrum of biomacromolecules. However, the effects of terahertz waves on biomacromolecules are largely unexplored. Although some progress has been reported, there are still numerous technical barriers to clarifying the relation between terahertz waves and biomacromolecules and to realizing the accurate regulation of biological macromolecules by terahertz waves. Therefore, further investigations should be conducted in the future. In this paper, we reviewed terahertz waves and their biomedical research advantages, applications of terahertz waves on biomacromolecules and the effects of terahertz waves on biomacromolecules. These findings will provide novel ideas and methods for the research and application of terahertz waves in the biomedical field.

scholarly journals MARVEL: measured active rotational–vibrational energy levels

2007 ◽  
Vol 245 (2) ◽  
pp. 115-125 ◽  
Author(s):  
Tibor Furtenbacher ◽  
Attila G. Császár ◽  
Jonathan Tennyson
Keyword(s):  
Vibrational Energy ◽  
Energy Levels ◽  
Vibrational Energy Levels
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