Semiempirical calculations of internal barriers to rotation and ring puckering. I. Present techniques

1975 ◽  
Vol 79 (5) ◽  
pp. 512-521 ◽  
Author(s):  
Leon L. Combs ◽  
Miles Holloman
Keyword(s):  
Semiempirical Calculations ◽  
Ring Puckering ◽  
Internal Barriers

An ab initio MO study of conformation structure of nicotinamide and its derivatives

1983 ◽  
Vol 48 (7) ◽  
pp. 1842-1853 ◽  
Author(s):  
Stanislav Böhm ◽  
Josef Kuthan
Keyword(s):  
Ab Initio ◽  
Wave Functions ◽  
Semiempirical Calculations ◽  
Rigid Rotor ◽  
Qualitative Similarity ◽  
Ab Initio Mo ◽  
Experimental Findings

Conformation of nicotinamide (I), 3-carbamoylpyridinium (IIa), 1-methyl-3-carbamoylpyridinium (IIb), and 1-methyl-1,4-dihydronicotinamide (IIIa) has been studied in the rigid rotor approximation on the basis of non-empirical STO-3G wave functions. The rotation barriers decrease in the order: IIIa > I ~ IIb > IIa. When confronted with semiempirical calculations, the conformation curves of molecular energy show a better qualitative similarity to the EHT than to NDDO and particularly to CNDO/2 curves. Relation of the calculated characteristics to experimental findings is discussed.

One-photon VUV-MATI and two-photon IR+VUV-MATI spectroscopic determination of oxetane cation ring-puckering vibrations and conformation

2021 ◽  
Vol 154 (5) ◽  
pp. 054308
Author(s):  
Do Won Kang ◽  
Sung Man Park ◽  
Chung Bin Park ◽  
Bong June Sung ◽  
Hong Lae Kim ◽  
...  
Keyword(s):  
Spectroscopic Determination ◽  
Two Photon ◽  
Ring Puckering

scholarly journals Internal barriers to efficiency: why disinvestments are so difficult. Identifying and addressing internal barriers to disinvestment of health technologies

2021 ◽  
pp. 1-16
Author(s):  
Bjørn Hofmann
Keyword(s):  
Health Care ◽  
Health Economics ◽  
Cognitive Biases ◽  
Care Practice ◽  
Core Concept ◽  
Health Care Practice ◽  
Health Technologies ◽  
Sound Foundation ◽  
Internal Barriers ◽  
Efficient Care

Abstract Although efficiency is a core concept in health economics, its impact on health care practice still is modest. Despite an increased pressure on resource allocation, a widespread use of low-value care is identified. Nonetheless, disinvestments are rare. Why is this so? This is the key question of this paper: why are disinvestments not more prevalent and improving the efficiency of the health care system, given their sound foundation in health economics, their morally important rationale, the significant evidence for a long list of low-value care and available alternatives? Although several external barriers to disinvestments have been identified, this paper looks inside us for mental mechanisms that hamper rational assessment, implementation, use and disinvestment of health technologies. Critically identifying and assessing internal inclinations, such as cognitive biases, affective biases and imperatives, is the first step toward a more rational handling of health technologies. In order to provide accountable and efficient care we must engage in the quest against the figments of our minds; to disinvest in low-value care in order to provide high-value health care.

Microwave spectrum and ring puckering motion in thiazolidine

1989 ◽  
Vol 137 (2) ◽  
pp. 354-361 ◽  
Author(s):  
Walther Caminati ◽  
Salvatore Di Bernardo
Keyword(s):  
Microwave Spectrum ◽  
Ring Puckering
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