Description:FIELD OF THE INVENTION
This invention relates to Effect of the electric field reduces the molecular vibration of C-N and C-C stretching of EBBA liquid crystal studied by DFT Methodology.
BACKGROUND OF THE INVENTION
The effect of an electric field on the molecular stretching of liquid crystals is a fundamental aspect of their behavior. Understanding this effect is crucial for both scientific exploration and 10 practical applications in industries like display technology and optics. In this study, we investigated the impact of an electric field on the molecular stretching behavior of EBBA (4-cyano-4'-n-pentylbiphenyl) liquid crystal. We observed that an increase in the electric field intensity led to a reduction in both C-N and C-C stretching within the EBBA liquid crystal molecule. Furthermore, the propagation of frequency ranges exhibited a decrease under 15 the influence of an elevated electric field. Notably, the heightened electric field caused the disappearance of previously observed frequencies while concurrently inducing the emergence of new frequencies associated with distinct stretching modes in the liquid crystal molecule. These newly appearing frequencies exhibit promising characteristics for potential applications in filtering and sensing across various fields. However, it is worth mentioning that excessively 20 high electric field strengths were found to have a detrimental effect on the liquid crystal, as indicated by the presence of negative frequencies in our results. Additionally, some frequencies were not prominently visible in the graphical spectra due to their low vibrational intensity, while high-intensity vibrational peaks were consistently observable in all spectra.
These findings contribute valuable insights into the response of EBBA liquid crystal to varying electric field strengths, offering potential applications in areas such as filtering and sensing, while also highlighting the importance of carefully managing electric field intensities to avoid adverse effects on the material.
US20190225521A1 discloses that Systems, apparatus, and methods for liquid treatment are provided including one or more of disinfection, filtration, and/or purification of the liquid using at least one electromagnetic field (EMF) including two or more specific and/or varying frequencies and pulses, the ENIFs optionally applied to the fluid using one or more of alternating current electricity, counter rotating magnetic fields, and/or oscillating electrical fields of 10 alternating polarity, in order to provide treated liquids for different uses, such as, but not limited to water treatment for drinking or other purposes. US10006859B2 discloses that an apparatus for detecting a material within a sample includes a light emitting unit for directing at least one light beam through the sample. A plurality of units receivesthe light beam that has passed through the sample and performs a spectroscopic analysis 15 of the sample based on the received light beam. Each of the plurality of units analyze a different parameter with respect to the sample and provide a separate output signal with respect to the analysis. A processor detects the material with respect to each of the provided separate output signals.
None of the prior art indicate above either alone or in combination with one another disclose 20 what the present invention has disclosed. This invention relates to Effect of electric field reduces the molecular vibration of C-N and C-C stretching of EBBA liquid crystal studied by DFT Methodology

SUMMARY OF THE INVENTION
This summary is provided to introduce a selection of concepts, in a simplified format, that are further described in the detailed description of the invention.
This summary is neither intended to identify key or essential inventive concepts of the invention and nor is it intended for determining the scope of the invention.
To further clarify advantages and features of the present invention, a more particular description of the invention will be rendered by reference to specific embodiments thereof, which is illustrated in the appended drawings. It is appreciated that these drawings depict only typical embodiments of the invention and are therefore not to be considered limiting of its scope. The invention will be described and explained with additional specificity and detail with the accompanying drawings.
The behavior of liquid crystal molecules is highly dependent on the phase they adopt, which, in turn, is influenced by the transition temperature at which the liquid crystal undergoes phase transitions. One of the commonly observed phases in liquid crystals is the smectic phase, which 15 is temperature-dependent. Smith et al. conducted experimental research that confirmed the presence of an even-odd effect in the transition from the nematic phase to the isotropic phase of liquid crystals. Additionally, they demonstrated the existence of the smectic phase specifically when the molecular structure included chain lengths of n=5 and 7 [1]. 20 To understand the properties of EBBA (4-cyano-4'-n-pentylbiphenyl) liquid crystals, researchers conducted experiments to calculate key parameters such as the order parameter, refractive indices, and polarizabilities. These calculations relied on data concerning the density 5 values of the liquid crystalline phase and the thermal expansion coefficient, along with the density of the crystal. Remarkably, the order parameter and refractive index of EBBA liquid crystals exhibit a decrease with increasing temperature until a specific point is reached [2]. The study also delved into the complex shear impedance of nematic compounds over a range of 5 frequencies from 50 to 150 kHz as a function of temperature. At the transition temperature, TC, a pretransitional state appears, marking the transition from isotropic to nematic phases. Interestingly, the complex shear results obtained closely match those observed in EBBA and MBBA [3]. Neubert et al. contributed to this field by proposing modified and unmodified stages for several 10 compounds based on temperature changes. Their method was applied in a temperature range extending to -20oC for the compound in question. It was observed that the transition from a crystalline state to mesophases occurs between 0.6 to 2.0oC, while the transition from mesophases to an isotropic phase takes place between 0.1 to 0.5oC. A variety of transitions can also be observed within the broader temperature range of 0 to 300oC [4]. The dielectric 15 properties of phenyl benzoate and Schiff-based liquid crystals were investigated using Onsager equations. This study shed light on the impact of dipole moments on oriented liquid crystals, as well as the contribution of isotropic and anisotropic factors to the orientational order parameter of the liquid crystals. The magnitude and sign of the anisotropy were determined based on group dipole moments of phenyl benzoate and Schiff-based liquid crystals [5]. 20 Prior to reaching its melting point, the compound enters a metastable state and generates heat. Metastable states are typically induced by rapidly cooling the compounds, resulting in the formation of the SC I form in the EBBA compound due to local structural packing [6]. Upon 6 rapid cooling, a metastable state with dielectric dispersion of the Debye type is observed down to -125oC. Below this temperature, a second dispersion region emerges due to the end groups in the structure. Notably, dielectric dispersion is absent in the stable state of the EBBA compound [7]. Furthermore, the vibrational states of the EBBA compound in its crystalline, 5 mesomorphic, and isotropic phases are influenced by external electric [8] and magnetic fields [9]. It's worth noting that the observed vibrational band primarily consists of internal vibrations, except for the 120 cm-1 frequency related to the long axis of the molecule [10]. Yasuniwa et al. conducted a comprehensive study of the vibrational spectra of both EBBA and MBBA compounds. They reported that the vibration of the end butyl chain is prominent at 280 10 cm-1 in the Raman spectra, confirming that the end butyl chain of EBBA tends to adopt all-trans conformations. NMR studies further revealed a dihedral angle of 43o [11]. The application of external electric and magnetic fields has a significant impact on molecular alignment. Kirov et al. and Wang et al. observed that in the presence of an electric field, the intensity of all Raman bands decreases without a change in their positions. They also suggested that the C-N stretching 15 mode at 2223 cm-1 is suitable for determining the orientational order [12-13]. Additionally, Wu et al. identified molecular vibration bands for C-H and C-N bonds, with absorptions centered at 3.4 µm and 4.5 µm, respectively [14]. Overall, liquid crystals exhibit switching behavior under the influence of external electric fields [15-16]. Changes in molecular orientation result in alterations in the threshold voltage required 20 to induce changes in the dielectric function of the compound [17]
COMPUTATIONAL METHODOLOGY
The optimization of EBBA liquid crystal molecules can be achieved through computational density-functional theory (DFT) using the B3LYP [18–19] method, a hybrid functional for Gaussian-type orbitals (GTOs), and the 6-31G** [20] basis set, which is implemented in the 5 NWChem software package [21].

BRIEF DESCRIPTION OF THE DRAWINGS
The illustrated embodiments of the subject matter will be understood by reference to the drawings, wherein like parts are designated by like numerals throughout. The following description is intended only by way of example, and simply illustrates certain selected embodiments of devices, systems, and methods that are consistent with the subject matter as claimed herein, wherein:
Figure 1. IR activity of EBBA liquid crystal molecule under electric field 0.00 a.u.
Figure 2. IR activity of EBBA liquid crystal molecule under electric field 0.01 a.u.
Figure 3. IR activity of EBBA liquid crystal molecule under electric field 0.02 a.u.
Figure 4. IR activity of EBBA liquid crystal molecule under electric field 0.03 a.u.
Figure 5. IR activity of EBBA liquid crystal molecule under electric field 0.04 a.u.
The figures depict embodiments of the present subject matter for the purposes of illustration only. A person skilled in the art will easily recognize from the following description that alternative embodiments of the structures and methods illustrated herein may be employed without departing from the principles of the disclosure described herein.
DETAILED DESCRIPTION OF THE INVENTION
The detailed description of various exemplary embodiments of the disclosure is described herein with reference to the accompanying drawings. It should be noted that the embodiments are described herein in such details as to clearly communicate the disclosure. However, the amount of details provided herein is not intended to limit the anticipated variations of embodiments; on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the scope of the present disclosure as defined by the appended claims.
It is also to be understood that various arrangements may be devised that, although not explicitly described or shown herein, embody the principles of the present disclosure. Moreover, all statements herein reciting principles, aspects, and embodiments of the present disclosure, as well as specific examples, are intended to encompass equivalents thereof.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a",” “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes” and/or “including,” when used herein, specify the presence of stated features, integers, steps, operations, elements and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components and/or groups thereof.
It should also be noted that in some alternative implementations, the functions/acts noted may occur out of the order noted in the figures. For example, two figures shown in succession may, in fact, be executed concurrently or may sometimes be executed in the reverse order, depending upon the functionality/acts involved.
In addition, the descriptions of "first", "second", “third”, and the like in the present invention are used for the purpose of description only, and are not to be construed as indicating or implying their relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" and "second" may include at least one of the features, either explicitly or implicitly.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which example embodiments belong. It will be further understood that terms, e.g., those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The behavior of liquid crystal molecules is highly dependent on the phase they adopt, which, in 15 turn, is influenced by the transition temperature at which the liquid crystal undergoes phase transitions. One of the commonly observed phases in liquid crystals is the smectic phase, which is temperature-dependent. Smith et al. conducted experimental research that confirmed the presence of an even-odd effect in the transition from the nematic phase to the isotropic phase of liquid crystals. Additionally, 20 refractive indices, and polarizabilities. These calculations relied on data concerning the density values of the liquid crystalline phase and the thermal expansion coefficient, along with the density of the crystal. Remarkably, the order parameter and refractive index of EBBA liquid 10 crystals exhibit a decrease with increasing temperature until a specific point is reached [2]. The study also delved into the complex shear impedance of nematic compounds over a range of frequencies from 50 to 150 kHz as a function of temperature. At the transition temperature, TC, a pretransitional state appears, marking the transition from isotropic to nematic phases. 5 Interestingly, the complex shear results obtained closely match those observed in EBBA and MBBA [3]. Neubert et al. contributed to this field by proposing modified and unmodified stages for several compounds based on temperature changes. Their method was applied in a temperature range extending to -20oC for the compound in question. It was observed that the transition from a 10 crystalline state to mesophases occurs between 0.6 to 2.0oC, while the transition from mesophases to an isotropic phase takes place between 0.1 to 0.5oC. A variety of transitions can also be observed within the broader temperature range of 0 to 300oC [4]. The dielectric properties of phenyl benzoate and Schiff-based liquid crystals were investigated using Onsager equations. This study shed light on the impact of dipole moments on oriented liquid crystals, as well as the contribution of isotropic and anisotropic factors to the orientational order parameter of the liquid crystals. The magnitude and sign of the anisotropy were determined based on group dipole moments of phenyl benzoate and Schiff-based liquid crystals [5]. Prior to reaching its melting point, the compound enters a metastable state and generates heat. Metastable states are typically induced by rapidly cooling the compounds, resulting in the 20 formation of the SC I form in the EBBA compound due to local structural packing [6]. Upon rapid cooling, a metastable state with dielectric dispersion of the Debye type is observed down to -125oC. Below this temperature, a second dispersion region emerges due to the end groups 11 in the structure. Notably, dielectric dispersion is absent in the stable state of the EBBA compound [7]. Furthermore, the vibrational states of the EBBA compound in its crystalline, mesomorphic, and isotropic phases are influenced by external electric [8] and magnetic fields [9]. It's worth noting that the observed vibrational band primarily consists of internal vibrations, 5 except for the 120 cm-1 frequency related to the long axis of the molecule [10]. Yasuniwa et al. conducted a comprehensive study of the vibrational spectra of both EBBA and MBBA compounds. They reported that the vibration of the end butyl chain is prominent at 280 cm-1 in the Raman spectra, confirming that the end butyl chain of EBBA tends to adopt all-trans conformations. NMR studies further revealed a dihedral angle of 43o [11]. The application of 10 external electric and magnetic fields has a significant impact on molecular alignment. Kirov et al. and Wang et al. observed that in the presence of an electric field, the intensity of all Raman bands decreases without a change in their positions. They also suggested that the C-N stretching mode at 2223 cm-1 is suitable for determining the orientational order [12-13]. Additionally, Wu et al. identified molecular vibration bands for C-H and C-N bonds, with absorptions centered at 3.4 µm and 4.5 µm, respectively [14]. Overall, liquid crystals exhibit switching behavior under the influence of external electric fields [15-16]. Changes in molecular orientation result in alterations in the threshold voltage required to induce changes in the dielectric function of the compound [17]
COMPUTATIONAL METHODOLOGY
The optimization of EBBA liquid crystal molecules can be achieved through computational density-functional theory (DFT) using the B3LYP [18–19] method, a hybrid functional for 12 Gaussian-type orbitals (GTOs), and the 6-31G** [20] basis set, which is implemented in the NWChem software package [21]
RESULTS AND DISCUSSION
Figure 1 displays the molecular geometry of EBBA liquid crystal. We have examined the impact of an electric field on the C-C and C-N stretching frequencies of EBBA liquid crystal. At an electric field strength of 0.00 atomic units (a.u.), the molecule exhibits energetic C-N atom stretching at a frequency of 1699 cm-1 , as well as C-H asymmetric stretching in the alkyl chain at a frequency of 3037 cm-1 , as shown in Figure 2 and Table 1. Increasing the electric field to 0.01 a.u. results in the molecules displaying strong C-N and C-C stretching in both benzene rings at a frequency of 1620 cm-1, along with H asymmetric stretching in the alkyl chain at a frequency of 3034 cm-1 , as illustrated in Figure 3 and Table 2. When the electric field is further increased to 0.02 a.u., the molecules exhibit H atom scissoring in the alkyl chain, H atom wagging in both benzene rings and the alkyl chain, all occurring at a frequency of 1397 cm-1 , along with H asymmetric stretching in the alkyl chain at a frequency of 2786 cm-1 , as depicted in Figure 4 and Table 3. At an electric field strength of 0.03 a.u., the molecules display stable H atom wagging in both benzene rings and the alkyl chain at a frequency of 904 cm-1 , along with C-H symmetric stretching in the alkyl chain at a frequency of 2553 cm-1 , as shown in Figure 5 and Table 4.
Table 1. EBBA liquid crystal with (0.00) electric field
S.No. Frequency (cm-1) Vibrational Coordinates
1. 744 C-C scissoring in both benzene ring
2. 857 C-C scissoring in both benzene ring
3. 1024 H atom wagging in linkage group
4. 1212 C-C stretching and H atom wagging in the benzene ring
5. 1380 In-plane H atom wagging in the alkyl chain
6. 1462 C-C stretching in the benzene ring
7. 1547 In-plane H atom wagging in both benzene ring
8. 1699 C-N atom stretching
9. 3037 C-H symmetric stretching in the alkyl chain
10. 3111 C-H asymmetric stretching in the alkyl chain
11. 3177 C-H asymmetric stretching in the benzene ring

Table 2. EBBA liquid crystal with (0.01) electric field
S.No. Frequency (cm-1) Vibrational Coordinates
1. 735 C-H and C-C twisting in benzene ring2
2. 843 H atom wagging in both benzene ring
3. 1007 C-C stretching in the alkyl chain
4. 1121 H atom wagging in the alkyl chain
5. 1191 H atom wagging in both benzene ring
6. 1369 H atom twisting in the alkyl chain and C-C asymmetric stretching in the benzene ring
7. 1457 H atom wagging in both benzene ring
8. 1620 C-N and C-C stretching in both benzene ring
9. 3034 H asymmetric stretching in the alkyl chain
10. 3107 H asymmetric stretching in the alkyl chain
11. 3185 H asymmetric stretching in the benzene ring

Table 3. EBBA liquid crystal with (0.02) electric field
S.No. Frequency (cm-1) Vibrational Coordinates
1. 604 H atom wagging in the benzene ring
2. 967 H atom twisting in benzene ring and linkage group
3. 1210 H atom wagging in both benzene ring and linkage
4. 1316 H atom wagging in the alkyl chain
5. 1397 H atom scissoring in alkyl chain H atom wagging in both benzene ring and alkyl chain
6. 1574 H atom wagging in both benzene ring
7. 1644 C-C stretching in both alkyl chain
8. 1679 C-N and C-C stretching in both benzene ring
9. 2786 H asymmetric stretching in the alkyl chain
10. 2689 H asymmetric stretching in the alkyl chain
11. 2987 H asymmetric stretching in the alkyl chain
12. 3146 H asymmetric stretching in the benzene ring

Table 4. EBBA liquid crystal with (0.03) electric field
S.No. Frequency (cm-1) Vibrational Coordinates
1. 669 H atom wagging in the benzene ring
2. 904 H atom wagging in both benzene ring and alkyl chain
3. 1037 H atom wagging in alkyl chain2 and the benzene ring
4. 1150 H atom wagging in alkyl chain1 and the benzene ring
5. 1277 C-N and C-C stretching
6. 1447 C-C stretching in both benzene ring
7. 1562 C-N and C-C stretching both benzene ring
8. 1676 C-N and C-C stretching in both benzene ring
9. 2553 C-H symmetric stretching in the alkyl chain
10. 2719 C-H symmetric stretching in the alkyl chain
11. 2862 C-H asymmetric stretching in the alkyl chain
12. 2944 C-H symmetric stretching in the alkyl chain

Table 5. EBBA liquid crystal with (0.04) electric field
S.No. Frequency (cm-1) Vibrational Coordinates
1. 556 H atom wagging in benzene ring and alkyl chain
2. 721 C-H atom twisting in benzene ring and alkyl chain
3. 901 H atom wagging in the alkyl chain and benzene ring
4. 1075 H atom wagging in alky chain
5. 1138 H atom wagging in the alkyl chain and both benzene ring
6. 1274 C-N and C-C stretching both benzene ring
7. 1575 C-C asymmetric stretching in both benzene ring
8. 1647 C-C asymmetric stretching in both benzene ring
9. 1673 C-N stretching in both benzene ring
10. 2316 C-H stretching in the alkyl chain
11. 2544 C-H asymmetric stretching in the alkyl chain
12. 2850 C-H symmetric stretching in the alkyl chain
13. 3063 C-H symmetric stretching in the alkyl chain

In this present invention, it has been observed that an increased applied electric field leads to a noticeable decrease in the C-N and C-C stretching frequencies of the EBBA liquid crystal molecule.
At an electric field strength of 0.00 atomic units (a.u.), the molecule exhibits C-C stretching at a frequency of 1462 cm-1 and C-N stretching at a frequency of 1699 cm-1.
When the electric field is increased to 0.01 a.u., the molecule displays C-C stretching at 1007 cm-1 and C-N stretching at a frequency of 1620 cm-1.
At 0.02 a.u. electric field strength, the molecule demonstrates C-C stretching at a frequency of 1644 cm-1 and C-N stretching at a frequency of 1679 cm-1.
Upon further increase to 0.03 a.u. electric field strength, the molecule expresses C-C stretching at a frequency of 1447 cm-1and C-N stretching at a frequency of 1676 cm-1.
Finally, at an electric field strength of 0.04 a.u., the molecule exhibits C-C stretching at a frequency of 1575 cm-1 and C-N stretching at a frequency of 1673 cm-1.
These findings have implications for the design of novel sensors and potential applications in filtration processes.
ADVANTAGES OF THE INVENTION
The present invention of the interaction of electric fields with the molecular structure and vibrations of EBBA has significant potential to advance various scientific and technological fields, with practical applications in materials science, electronics, and beyond.
REFERENCES
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, Claims:1. A method for studying the effect of an electric field on the molecular vibration of EBBA liquid crystal, comprising:
Providing an EBBA liquid crystal molecule;
Performing computational density-functional theory (DFT) calculations on the EBBA liquid crystal molecule using the B3LYP method and a 6-31G** basis set;
Analyzing the molecular vibrations of the EBBA liquid crystal molecule in the presence of varying electric fields.
2. The method as claimed in claim 1, wherein the molecular vibrations analyzed include C-N and C-C stretching in both benzene rings and H asymmetric stretching in the alkyl chain.
3. The method as claimed in claim 1, wherein the electric field is increased incrementally and the corresponding changes in molecular vibrations are observed.
4. The method of claim 1, wherein the molecular vibrations analyzed include H atom scissoring and H atom wagging in the alkyl chain and both benzene rings.