INDO [intermediate neglect of differential overlap] theoretical studies. III. INDO theoretical study of the geometry of fluorinated methyl and allylic cations and radicals

1972 ◽  
Vol 94 (17) ◽  
pp. 5979-5985 ◽  
Author(s):  
Lowell D. Kispert ◽  
Charles U. Pittman ◽  
D. Lee Allison ◽  
T. B. Patterson ◽  
Charles W. Gilbert ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Theoretical Studies ◽  
Neglect Of Differential Overlap

P2S2-Bridged binuclear metal carbonyls from dimerization of coordinated thiophosphoryl groups: a theoretical study

2020 ◽  
Vol 44 (30) ◽  
pp. 12942-12948
Author(s):  
Zhong Zhang ◽  
Zuqing Chen ◽  
Zhipeng Yang ◽  
Jianping Wang ◽  
Liang Pu ◽  
...  
Keyword(s):  
Theoretical Study ◽  
Theoretical Studies ◽  
Metal Carbonyls ◽  
Binuclear Metal

Theoretical studies indicate the complexes M(CO)n(PS) with bent 1-e/2-e donor PS groups to be unstable for giving the stable M(CO)n−1(PS) with linear 3-e donor PS groups. In addition, only Mn2(CO)8(P2S2) is energetically viable from the Mn(CO)4(PS).

Theoretical Study of Ethylene Addition to O=W(=CH2)(CH3)2

2007 ◽  
Vol 62 (3) ◽  
pp. 367-372 ◽  
Author(s):  
Robin Haunschild ◽  
Gernot Frenking
Keyword(s):  
Density Functional ◽  
Theoretical Study ◽  
Activation Barrier ◽  
Reaction Pathways ◽  
Theoretical Studies ◽  
Stable Isomer ◽  
Functional Theory ◽  
B3lyp Level ◽  
Rhenium Compound ◽  
Favorable Reaction

Quantum chemical calculations using density functional theory at the B3LYP level of theory were carried out to investigate the reaction pathways for the addition of ethylene to WO(CH3)2(CH2) (W1). The results are compared to those of previous theoretical studies of the ethylene addition to OsO3(CH2) (Os1) and ReO2(CH3)(CH2) (Re1). The theoretically predicted reactions pathways exhibit significant differences. The energetically most favourable reaction of the tungsten system W1 is the [2+2]W,C addition across theW=C double bond yielding the metallacyclobutane W3a which then rearranges to the slightly more stable isomer W3b. The [2+2]Re,C addition of the rhenium compound yielding the metallacyclobutane Re3a has the lowest activation barrier for the ethylene addition to the rhenium system, but the reaction is endothermic while the exothermic formation of the more stable isomer Re3b has a much higher activation barrier. The [3+2]C,O addition Os1+C2H4→Os2 is the thermodynamically most favorable reaction of the osmium compound.

Experimental and theoretical studies of the mica polymorphs

1956 ◽  
Vol 31 (234) ◽  
pp. 209-235 ◽  
Author(s):  
J. V. Smith ◽  
H. S. Yoder
Keyword(s):  
Growth Mechanism ◽  
Theoretical Study ◽  
Dominant Role ◽  
Spiral Growth ◽  
Theoretical Studies ◽  
X Ray ◽  
Layer Cell ◽  
Triclinic Structure ◽  
Experimental And Theoretical Studies ◽  
Made In

SummaryAn experimental and theoretical study has been made in order to determine the number and the structure of the possible polymorphs and to determine the structural relations between them. The simplest structures are 1M, 2M1, 2M2, 3T, 20, and 6H polymorphs, and more complicated types can be developed. Some of the previously described polymorphs were not contained in the theoretical list and were re-examined. The 6M structure was found to be a 2M2 polymorph, the 6-layer triclinic type was found to be a 2M1 polymorph, and the 3M structure was shown to be a 3T type. The 24-layer triclinic structure could be described on a simpler 8-layer cell. This type together with a new 12-layer monoclinic structure, as well as other structures of higher periodicity, presumably consists of complex stacking and results from spiral-growth mechanism. Two extreme types of layer-disordered crystals may be built and a disorder of individual ions may also occur. Single stacking faults result in twinned crystals. A new twin relation (180° rotation about the [100] axis) has been recognized. Twenty specimens from extreme geological environments have been examined in order to evaluate the control of environment on the stacking. The type of stacking could not be attributed solely to the influence of pressure and temperature. Composition appears to play a dominant role in the type of stacking, and semi-quantitative structural arguments appear to support this contention. The influence of growth mechanism is discussed. A scheme for the identification of the mica polymorphs by X-ray powder and single-crystal methods is given.

scholarly journals Performance Analysis of Maximal Risk Evaluation Formulas for Spectrum-Based Fault Localization

2020 ◽  
Vol 10 (1) ◽  
pp. 398 ◽  
Author(s):  
Tingting Wu ◽  
Yunwei Dong ◽  
Man Fai Lau ◽  
Sebastian Ng ◽  
Tsong Yueh Chen ◽  
...  
Keyword(s):  
Risk Evaluation ◽  
Theoretical Study ◽  
Ordered Set ◽  
Fault Localization ◽  
Research Area ◽  
Theoretical Studies ◽  
Effectiveness Analysis ◽  
Significant Research ◽  
Program Spectrum ◽  
Better Than

The effectiveness analysis of risk evaluation formulas has become a significant research area in spectrum-based fault localization (SBFL). The risk evaluation formula is designed and widely used to evaluate the likelihood of a program spectrum to be faulty. There are numerous empirical and theoretical studies to investigate and compare the performance between sixty risk evaluation formulas. According to previous research, these sixty risk evaluation formulas together form a partially ordered set. Among them, nine formulas are maximal. These nine formulas can further be grouped into five maximal risk evaluation formula groups so that formulas in the same group have the same performance. Moreover, previous research showed that we cannot theoretically compare formulas across these five maximal formula groups. However, experimental data “suggests” that a maximal formula in one group could outperform another one (from a different group) more frequently, though not always. This inspired us to further investigate the performance between any two maximal formulas in different maximal formula groups. Our approach involves two major steps. First, we propose a new condition to compare between two different maximal formulas. Based on this new condition, we present five different scenarios under which a formula performs better than another. This is different from the condition suggested by the previous theoretical study. We performed an empirical study to compare different maximal formulas using our condition. Our results showed that among two maximal risk evaluation formulas, it is feasible to identify one that can outperform the others more frequently.

Theoretical studies of azapentalenes. Part 4: Theoretical study of the properties of 3a,6a-diazapentalene

Tetrahedron ◽  
2009 ◽  
Vol 65 (29-30) ◽  
pp. 5760-5766 ◽  
Author(s):  
Ibon Alkorta ◽  
Fernando Blanco ◽  
José Elguero
Keyword(s):  
Theoretical Study ◽  
Theoretical Studies

INDO [intermediate neglect of differential overlap] theoretical study of conjugation into and through the cyclopropane ring

1971 ◽  
Vol 93 (25) ◽  
pp. 6948-6953 ◽  
Author(s):  
Lowell D. Kispert ◽  
Catherine Engelman ◽  
Charles Dyas ◽  
Charles U. Pittman
Keyword(s):  
Theoretical Study ◽  
Cyclopropane Ring ◽  
Neglect Of Differential Overlap

Intermediate neglect of differential overlap theoretical studies. 2-Substituted 1,3-dioxolan-2-ylium ions

1973 ◽  
Vol 38 (3) ◽  
pp. 471-475 ◽  
Author(s):  
Charles U. Pittman ◽  
Thurman B. Patterson ◽  
Lowell D. Kispert
Keyword(s):  
Theoretical Studies ◽  
Neglect Of Differential Overlap
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