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Govani, Jayesh

Joshi, Mihir J

Indian! Phys. 82 (11), 1485-1494 (2008) 
Growth and characterization of gel grown potassium 
hydrogen levo- tartrate crystals 
Jayesh Govani1 and Mihir J Joshlr 
Materials Science and Engineering Department, University of Texas at El Paso, hi Paso, TX 79968 U S A 
2Crystal Growth Laboratory, Department of Physics, Saurashtra University, Rajkot 360 005, Gujarat, India 
E mail mshilp24iforediffmail com 
Received 29 February 2008, accepted U June, 2008 
Abstract Potassium hydrogen levo-tartrate (KHLT) crystals were grown by the single diffusion gel growth 
technique in silica hydro gel medium Potassium chloride containing supernatant solution was poured on tartaric 
acid impregnated set gel KHLT crystals in dendritic form were grown near the gel-liquid interface and prismatic 
crystals were grown at the bottom of the test tubes Sodium chloride solution was added in different amounts to 
potassium chloride containing supernatant solution and its effect was studied in terms of change in crystal 
morphology, crystal dimension and number of grown crystals The powder XRD analysis confirmed the growth 
of single-phase KHLT crystals The grown crystals were characterized by FT-IR and thermo-gravimetric analysis 
The crystals were found to be thermally stable up to 300 °C and decompose into oxide on further heating The 
kinetic parameters of decomposition were estimated by employing two different relations, viz, the Coats and 
Redfern relation as well as the Horowitz and Metzger relation The thermodynamic parameters of decomposition 
were also calculated 
Keywords Gel growth, FTIR, powder XRD, TGA, Kinetic and thermodynamic parameters 
PACS No. 81 10 Dn, 82 70 Gg, 65 40 G 
1. Introduction 
There are numerous applications of tartrate compounds in science and technology [1]; 
for example, calcium tartrate [2], sodium-potassium tartrate [3] and rubidium hydrogen 
tartrate [4] exhibit ferroelectric applications; sodium ammonium tartrate [5], rubidium 
hydrogen tartrate [4] can be used for ferroelectric and ferro-elastic applications and lithium 
thiallate tartrate [6] exhibits dielectric applications 
Corresponding Author 
©2008IACS 
1486 Jayesh Govani and MihirJJoshi 
Gel growth is the simplest technique under ambient condition, which is suitable for the 
crystal growth of compounds sparingly soluble in water and decomposes at low temperature 
[7] However, attempts have been made to grow crystals, which are soluble in water, by 
the gel-growth technique [8-10] Since, gel growth technique has several advantages over 
few disadvantages, it has attracted the attention of several researchers Several crystals 
of various tartrates have been successfully grown in the author's laboratory and 
characterized, which includes calcium tartrate [11], iron tartrate [12], zinc tartrate [13] 
cadmium tartrate [14], iron-manganese mixed levo-tartrates [15], calcium-strontium mixed 
calcium levo-tartrates [16], Mn*+ and Cu++ doped calcium levo-tartrate [17,18] 
Potassium hydrogen tartrate (KHT), also known as cream of tartar or potassium 
bitartrate, possesses many applications and some of them are patented, for instance in 
chemical removal of dental plaque [19] and in treatment of infectious and viral diseases 
[20] The formation of KHT crystals in wine bottles is unwanted and efforts are made to 
avoid it by a trap process or by influence of external electric field [21] The nucleation 
study of KHT in model solutions and wines is reported [22] In the earlier studies KHT 
crystals have been grown by solution growth technique and hillocks, macro-spirals and 
growth layers of typical features were observed [23] A method has been developed for 
growing KHT crystals of cross-shaped in a gel-matrix and patented [24] 
The aim of the present study is to grow KHLT (potassium hydrogen levo-tartrate) crystals 
by the single diffusion gel growth technique and characterize them by different techniques 
as well as to study the effect of addition of sodium chloride solution in supernatant solution 
on the growth of crystals 
2. Experimental 
For crystallization, glass test tubes of 25 mm diameter and 140 mm length were used 
Sodium metasilicate solution of density 1 06 gm/cm3 was used for preparation of the gel 
One molar levo tartaric acid mixed with sodium metasilicate solution and the pH of the 
mixture was kept at 3 6 to 3 8 The mixture was poured in different test tubes to set in to 
the gel The supernatant solutions containing different proportions of 1 M sodium chloride 
and 1 M potassium chloride solutions were gently poured without disturbing the gel surfaces 
and the volume of the mixture was maintained at 10 ml 
The growth of crystals was completed within a month For pure potassium chloride 
containing supernatant solution, the dendritic crystals were grown at the liquid-gel interface 
and their branches extended nearly 1 cm in to the gel Prismatic single crystals were 
grown at the bottom Whereas for higher volumes of sodium chloride, no single crystal 
growth was observed at the bottom of test tubes and a few bi-crystals were grown at the 
gel-liquid interface Crystal growth was not observed in the case of pure sodium chloride 
even after four months Which indicated clearly that sodium tartrate crystals were not 
grown but sodium chlonde in the supernatant solution influenced the growth and morphology 
of crystals 
Growth and characterization of gel grown potassium hydrogen levo-tartrate crystals 1487 
Figure 1(a, b) is the photograph for supernatant solution containing pure potassium 
chloride exhibiting top and bottom view of the test tube, respectively It can be observed 
that dendritic crystals are grown at the gel-liquid interface and at the bottom of the gel 
prismatic single crystals are grown. 
(a) 
Figure 1. Crystal growth of KHLT crystals, (a) dendritic crystals at gel-liquid interface and (b) single 
crystals at the bottom of test tube. 
3. Characterization techniques 
The FT-IR spectra of powdered samples in KBr medium were recorded on Specord IR 75, 
Carl Zeiss (Germany) in the range of 400-4000 cm"1. Powder XRD analysis was carried 
out using a PW 1710 diffractometer with Cu-Ktt radiations. Thermo-gravimetric analysis 
(TGA) on powdered samples was carried out from room temperature to 900°C in the 
atmosphere of air at a heating rate of 20°C/min. 
4. Results and discussion 
In the present investigation, the KHLT crystals were grown by gel growth method. The 
dendritic growth of crystals at the gel-liquid interface and prismatic growth of crystals at 
the bottom of gel column was observed. This may be due to high value of concentration 
gradient in the diffusion column at the gel-liquid interface leading to dendritic growth and 
comparatively lesser concentration gradient allows prismatic and good quality crystals to 
grow. 
1488 Jayesh Govani and MihirJ Joshi 
FTIR spectrum of KHLT is shown in Figure 2. It can be observed from the figure that 
the absorptions at 3317 cm*1 and 3271 cm*1 are due to O-H stretching vibrations 
representing water of crystallization or moisture on the surface. The absorption at 2975 
cm"1 is due to C-H stretching vibration. The absorptions at 1869 cnrr1, 1718 cm1 and 
1560 cm*1 are due to C=0 stretching vibration. The absorptions at 1409 cm"1 and 1338 
cm1 are due to O-H stretching in plane of deformation. Whereas, the absorptions at 1306 
cnr\ 1264 cm"1, 1213 cm"1, 1134 cnrr1, 1067 cnrr1 all are due to C-0 stretching and C* 
OH moiety. Similarly, the absorptions at 904 cm*1, 878 cm"1, 842 cm*1, 789 cm*1 and 680 
cm1 are due to O-H deformation out of plane and C-H stretching vibrations. The absorptions 
at 619 cm*1, 573 cm"1, 522 cm*1 and 486 cm'1 are due to metal-oxygen stretching vibration 
However, this spectrum is slightly different from the spectra obtained for calcium and 
strontium levo tartrate and for pure and mixed manganese and iron levo tartrate, which 
may be due to hydrogen is chelating the tartrate radical with metallic ion in form of 
potassium hydrogen tartrate. 
4000 3000 2000 
Wavenumber Jem'1) 
10000 
Figure 2. FTIR spectrum of KHLT crystals. 
Also, FT-IR and Raman spectra of ammonium hydrogen tartrate (AHT) and KHT have 
been reported earlier [25]. From the FTIR spectrum the presence of water of crystallization 
or moisture attached to the crystal, C-H bond, the C=0 bond and the metal -oxygen 
bond were identified. 
Figure 3 shows the powder XRD pattern of the sample. The cell parameters are 
calculated by using the computer programs DEBYE and REFEDTBAS, which are as 
follows: 
a = 7.789(1) A, b = 10.648(3) A , c = 7.611(4) A, Cell volume = 631.23 (A)3 and 
orthorhombicity -15.50. 
These unit cell parameters are identical for all the samples grown with different amount 
of sodium chloride in the supernatant solutions. These cell parameters exactly match 
Growth and characterization of gel grown potassium hydrogen levo-tartrate crystals 1489 
with the cell parameters of the potassium hydrogen tartrate (KH5C406 or KHC4H406) 
reported in the ASTM data card for the powder XRD. This indicates that all crystals grown 
are potassium hydrogen tartrate crystals and no mixed crystals of potassium and sodium 
tartrate are formed. In earlier attempts, the structure of KHT at 100 K has been reported 
[26]. 
Figure 3. Powder XRD patterns of KHLT crystals 
The thermal stability of crystals and kinetics of dehydration have been studied by 
employing thermogravimetry for several tartrate compounds [12-16, 27]. Figure 4 shows 
the thermogram of sample. The sample starts decomposing at 280°C and it suddenly 
decomposes into meta stable KOHC03, which is occurring at 290°C, thereafter, the sample 
further decomposes into K20 at 320 °C, and finally decomposes into KO+ (3/2)0 at 460 
°C and remains stable up to the end of the analysis. No water of hydration is found to be 
associated with the crystals. Table 1 is of theoretical and practical values of weight-
losses at different temperatures. The thermo-grams for all other samples are found to be 
nearly the same. 
1490 Jayesh Govani and MihirJ Joshi 
This indicates that the NaCI solution in the supernatant solution does not grow mixed 
potassium sodium tartrate crystals but only grow potassium hydrogen tartrate crystals 
The NaCI solution modifies the morphology of crystals The failure of growing sodium 
tartrate crystals may be due to high solubility product of sodium tartrate and the presence 
of large amount of sodium hydroxide and sodium chloride in the solution and gel Sodium 
hydroxide is present in the gel due to polymerization of monosilicic acid 
100 
90 
80 
§ 60 
50 
40 
" 
, i i i U. 1 t 
l 
± 1 1 
100 200 300 400 500 
Temperature/°C 
600 700 800 
Figure 4. Thermogram of KHLT crystals 
Many researchers have used thermo gravimetric data to calculate the kinetic parameters 
of solid-state reaction including weight loss [12, 14, 28-30] By using the kinetic parameters 
of pyrolysts such as order of reaction, frequency factor and energy of activation the 
shape of curve is determined With the help of Coats and Redfern [28] relation the kinetic 
parameters were calculated Coats and Redfern relation is given by 
log 10 
1-rt 
1-(1-ar) 
r 2 (1 -n ) 
J j'°9io AR aE 2RT 2ZRT (D 
Where a = {WQ -W)/(W0 -Wf), W0the initial weight, W the weight at time f, W, the 
final weight, n the order of reaction, A the frequency factor, E the activation energy of the 
reaction, R a gas constant, and a the heating rate in °C/min 
Table 1. Thermal decomposition of KHLT crystals 
Sample 
KH5C406 
KOHCO3 
K20 
KO+ 3/20 
Temperature 
in °C 
260 
290 
320 
460 
Theoretical 
weight % 
100 
61 71 
50 08 
42 04 
Observed 
weight % 
100 
60 
46 
42 
Growth and characterization of gel grown potassium hydrogen levo-tartrate crystals 1491 
To determine the value of activation energy and order of reaction, a plot of 
l<#io { 1 ~ ( 1 ~ a ) j / { r 2 ( 1 ~ n ) } j versus 1/7" »s drawn for different values of n and the 
best linear plot gives the correct values of n This equation is valid for all values of n 
except n = 1 
Figure 5 is a plot of Coats and Redfern equation for the crystals grown by using pure 
potassium chloride The values of activation energy, frequency factor and the order of 
reaction are found to be 191 47 kJ mol \ 61 93 * 1027 and 2/3, respectively 
Horowitz and Metzger [29] obtained equation for pyrolysis, where only a fraction of 
total weight is lost as in the loss of water of hydration from a hydrated salt Horowitz and 
Metzger relation is given by 
log 10 
1-C 1 n 
1-n 2303 s (2) 
where C = (W - Wf)l(W0 - Wf)} W0 initial weight , Wf the final weight, E the activation 
energy, and n the order of reaction 
5 75 
5 50 
5 25 
1 80 1 85 1 90 
1 i * io~3 
Figure 5 A plot of Coats and Redfern relation for KHLT crystals, Where Y = \OQW[{1~C\- a^lU^-n)}] 
and X = 1/7 
A plot of log10[1 - C1~n)/(1 - n)] versus 6 gives best straight line with its slope equal 
to E/RT$2 Figure 6 is a plot of Horowitz-Metzger relation for the crystals grown by using 
pure potassium chloride From the plot the values of activation energy and order of reaction 
are found to be 210 70 kj mol1 and 2/3, respectively The difference in the values of 
kinetic parameters obtained by Coats and Redfem as well as Horowitz and Metzger relations 
are due to different mathematical models used in these equations Notwithstanding, these 
1492 Jayesh Govani and MihirJJo$h, 
two equations employ the Arrhenius law in analysis, but subsequent mathematical 
treatments and assumptions differ, which gives two different equations This has been 
discussed by Dabhi and Joshi [13] 
Figure 6 A plot of Horowitz and Metzger relation for KHLT crystals Where Y = log10[1-C1~°)/(1-n)] and X 
= 0 
The thermodynamic parameters have been evaluated from the decomposition stage of 
thermogram of potassium tartrate crystals using the standard relations [31] The standard 
enthalpy of activation J*H° was calculated by using the following relation 
J*H°=E-2RT <3> 
The standard entropy of activation J*S° was calculated by using the relation 
J *S°=2 303xRxlog 10 
Ah 
kT„ (4) 
Where, k is the Boltzman constant, h the Planck constant, Tm the temperature and A the 
frequency factor 
The standard Gibbs energy of activation, /pQ0 is estimated by using the following 
equation, 
j>G°=J>HQ-TJS0 (5) 
Estimated values of standard enthalpy, standard entropy and standard Gibbs free 
energy are 182 16 kJMol"1 , 130 73 kJMoh1 and 108 95 kJMol"1, respectively 
The values of different thermodynamic parameters obtained for different samples Positive 
values of the standard enthalpy and the standard entropy of activation suggest that the 
Growth and characterization of gel grown potassium hydrogen levo-tartrate crystals 1493 
process is spontaneous at high temperatures and the positive value of standard Gibbs 
free energy suggests the process is thermodynamically unstable 
5. Conclusion 
Pure Potassium hydrogen levo tartarte (KHLT) crystals were grown using gel growth 
technique and crystals were characterized by different techniques The powder X-ray 
diffraction analysis confirmed single-phase compound Comparing with standard ASTM 
data for powder X-ray diffraction it has been found that all grown crystals are KHLT crystals 
From thermo-gravimetnc analysis crystals are found to be thermally stable up to 280° C 
and they decompose into oxide through the short meta -stable state of KOHC03 Different 
volumes of sodium chloride solutions in supernatant solution affect the morphology but do 
not grow doped or mixed crystals The same nature of Powder XRD patterns, FT-IR spectra 
and thermograms for various samples indicate the formation of only one compound that 
is KHLT 
Acknowledgment 
The authors are thankful to Prof K N Iyer (Saurashtra University, India) and Dr Felicia 
Manciu (University of Texas at El Paso, U S A ) for their keen interest The author (Dr M 
J Joshi) is thankful to UGC, New Delhi, India, for SAP grants 
References 
[1] G A Kiosse Crystal Structure of Inorganic Compounds, (Kishinev Shtinsta Press) (1974) 
[2] H B Gon J Crystal Growth 102 521 (1990) 
[3] J Valasek Phys Rev 17 475 (1921) 
[4] C C Desai and A H Patel J Mater Set Lett. 8 361 (1989) 
[5] K Aizu J Phys Soc Jap 31 1521 (1971) 
[6] E Sawaguchi and L E Cross Ferroelectncs 2 37 (1971) 
[7] H K Henish "Crystal Growth in Gels" (Pennsylvania Univ Press University Park) (1970) 
[8) D A Glocker and I F Soest J Chem Phys 51 3143 (1969) 
[9] B Brezina and J Havrankova Mater Res Bull 87 537 (1971) 
[10] K Ambujam Study on the growth and charactenzation of NLO active single crystals of KDP y-
glycine, BGHC, CMTC and ZMTC, Ph D Thesis, University of Madras (2005) 
[11) V S Joshi and M J Joshi Indian J Phys 75A 159 (2001) 
[12] S Joseph and M J Joshi Indian J Phys 71A 183 (1997) 
[13] R M Dabhi and M J Joshi Indian J Phys 76 A 211 (2002) 
[14] R M Dabhi and M J Joshi Indian J Phys 76 A 481 (2003) 
[15] S J Joshi, B B Parekh, K D Vohra and M J Joshi Bull Mater Sci 29 307(2006) 
[16] K D Pankh, B B Parekh, D J Dave and M J Joshi Indian J Phys 80 719(2006) 
[17] S R Suthar and M J Joshi Cryst Res and TechnoL 41 664(2006) 
[18] S R Suthar, S J Joshi, B B Parekh and M J Joshi Indian J Pure Appl Phys 46 48 (2007) 
[19] US Patent no 64819675, "Chemical removal of dental plaque " 
1494 Jayesh Govani and MihirJJoshi 
[20] US Patent no 4708952, "Method of treatment of infectious and viral diseases by one time 
interference " 
[21] V Guillet, N Gabas, M Comtat and J L Favarel J Appl Etectrochem 32 1313 (2002) 
[22) M A Lafortune, E M Henning, M J Lake, V Gerbaud, N Gabas, C L Lagurie and J Bloum j 
Cryst Growth 166 172 (1996) 
[23] K Sangwal and S Veintemillas-Verdaguer Cryst Res And Technol 29 634 (1994) 
[24] US Patent no 6793732, Method and Kit for growing Cross shaped crystals. 
[25] P Kolandaivel and S Selvasekarapandian Cryst. Res and Technol. 28 665 (1993) 
[26] J Bushmann and P Luger, Acta Cryst C41 206 (1985) 
[27] M M Abdul-Kader, 2 H El-Tanahy, A Abdul Razik, M Abdutaleb and A El-Shawarby J. Mater Sci 
Materials in Electronics 6 178 (1995) 
[28] A W Coats and J P Redfern Nature 201 183 (1964) 
[29] H H Horowitz and G Metzger Anal Chem 35 1464 (1963) 
[30] P N Kotru, K K Rama and M L Koul, J Mater Sci 21 3933 (1986) 
[31] K J Laidler Chemical Kinetics (New York Harper and Row) (1987) 


Growth and Characterization of Gel Grown Potassium Hydrogen Levotartrate Crystals

Uttam, K N

Singh, Renu

Tandon, Pavitra

Indian J. Phys.Wl(\\)% 1523-1527(2008) 
A new band system of the MgBr molecule 
K N Uttam*, Renu Singh and Pavitra Tandon 
Sana's Spectroscopy Laboratory, Department of Physics, 
Allahabad University, Allahabad-211 002, India 
L mail kailash uttam<&rediifm<*il cum 
Received 21 January 200S, accepted 29 May 2008 
Abstract • An electronic emission spectrum of magnesium monobromide molecule, excited in high temperature 
furnace, has been photographed in the /U 3600 - 4050 A region at reciprocal linear dispersion of 7 3 A/mm The 
study reveals the presence of a new band system, B - X in AX 3600 - 3800 A region About 16 single headed 
bands, degraded to higher wavelength side, have been attributed to this system The vibrational analysis 
performed suggests that the system arises from the ground state involving transition B21 - X21 The vibrational 
constants have been determined for the relevant states 
Keywords thermal emission technique, Spcctium of the MgBr molecule Vibrational analysis 
PACS No. 33 20Kf 
1. Introduction 
Magnesium monobromide molecule (MgBr) has been the subject of a large range of 
spectroscopic studies [1-8]. Several optical absorption and emission studies were concerned 
with the ground and low-laying excited states of the neutral species, leading to information 
about energetics, vibrational frequencies, equilibrium bond lengths and dissociation energies 
Six electronic transitions have been identified, all involving the ground electronic states 
viz. A2n - X2E (AA 3659 - 4033 A), C2Z-X2Z ( /U2540 - 2720 A) D2I-X2Z 
( ^ 2 0 8 5 - 2 1 2 5 A), E2n-X2I {AA 2060 - 2125 A), F2E- X2I(AA 2035 - 2075A) 
and G2n - X2E (AA 2045 - 2080 A). In addition Yamdagni [9] photographed nine entirely 
new bands in the region AA 3660 - 3790 A in absorption but due to weak and diffuse 
bands he could not propose any vibrational assignments The rotational study of the 
A2n - X2E band system has been performed by Walker and Gerry [10] and Hirao ef at 
Corresponding Author 
©2008IACS 
1524 K N Uttam, Renu Singh and Pavitra Tandon 
[11] using high resolution Fourier Transform Spectrometer and reported improved rotational 
constants 
While six band systems have been reported for the MgBr molecule, the study of Mgi 
molecule in emission as well as in absorption has disclosed the presence of four systems 
viz A, B, C, and D in the AA 3600 - 4000 A region The study of the MgCI molecule m 
thermal emission by Uttam et a/ [12] has revealed the presence of a large number of new 
bands in the region AA 3660 - 3790 A Since MgCI, MgBr, Mgl molecules are isovalent 
molecule, similar band systems for the MgBr molecule can be reasonably expected 
Since thermal emission is a low energy excitation, the spectra involving much higher 
energy states generally do not appear Thermally excited emission spectra are found to 
be almost free from atomic lines In most cases, the spectrum obtained by this method 
involves the ground state and the lower electronic states of the system Therefore we 
decided to examine the spectrum of MgBr molecule using high temperature graphite furnace 
We have been able to record the thermal emission spectrum of the MgBr in the 
AA 3600-4000 A region using a high temperature vacuum graphite furnace Here we report 
the first vibrational analysis of a new system B21 - X2S 
2. Experimental details 
A small quantity of pure solid magnesium bromide (BDH, 98%) was put into the 
experimental tube of the Saha's high temperature graphite furnace [13] After evacuation 
the furnace chamber was filled with argon gas at about a pressure of 500 Torr to prevent 
a rapid effusion of molecular vapour from the open ends of the carbon tube A temperature 
of about 2400°C was raised and the spectrum was recorded in first order of 2-m plane 
grating spectrograph equipped with a grating blazed at A 5600 A and total lines ruled 
45500 at a reciprocal linear dispersion of 7 3 A/mm An exposure time of about 12 mm 
was found sufficient to record a good spectrogram on ILFORD 400 ASA black and white 
film in first order The iron arc spectrum was recorded for calibration lines The spectra 
were measured on an Abbe Comparator with the least count of 0 0001 cm 
3. Results and discussion 
The thermal emission spectrum of the MgBr molecule has been photographed in the 
AA 3600 - 4000 A region A part of the spectrum is reproduced in Figure 1 The A - X 
system has been recorded in AA 3659 - 4033 A region along with some new bands The 
spectrum is free of atomic lines Contrary to the suggestion of Yamdagni [9], the bands 
could be seen in the spectrogram and are measured accurately About 16 single headed 
bands, degraded to longer wavelength side, have been recorded in the region AA 3600 -
3800 A The observed bands has been classified into jv = 0, ±1, ±2 sequences of a new 
system B - X The bands of B-X system can be described by the expression 
v = ve + coe\v' + ~ i f ./.... 1 •".X.K + -J ~ < ^ +2} +«vq^'+~ 
A new band system of the MgBr molecule 1525 
Figure 1. Thermal emission spectrum of MgBr molecule at a reciprocal linear dispersion of 7 3 A / mm 
The following vibrational constants have been determined from the vibrational analysis 
using Deslandre Table 
vQQ -- 26924 0 «>; - 357, (,>ex'e ~ 2 0 cm~1 
< - 374 2 , «>ex; - 1 2 cm"1 
Table 1. Band Head Data of the B'l ~X21 System of the MgBr Molecule 
SNo 
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
vca/ (cm"1) 
26182 8 
26168 8 
26552 2 
26535 8 
26517 8 
26924 0 
26905 2 
26884 8 
26862 8 
26839 2 
26814 0 
27277 0 
27254 2 
27229 8 
27203 8 
27626 0 
Vobs (cm-1) 
26182 0 
26167 3 
26553 0 
26534 7 
26516 7 
26924 0 
26904 2 
26883 9 
26862 3 
26840 2 
26813 7 
27279 0 
27255 1 
27228 7 
27203 4 
27626 5 
{v'.V) 
(0.2) 
(1.3) 
(0.1) 
(1.2) 
(2.3) 
(0,0) 
(1.1) 
(2.2) 
(3,3) 
(4,4) 
(5,5) 
(10) 
(2 1) 
(3,2) 
(4,3) 
(2,0) 
Inten 
2 
1 
3 
2 
1 
5 
4 
3 
2 
1 
1 
2 
2 
1 
1 
1 
1526 K N Uttam, Renu Singh and Pavitra Tandon 
The band head data, visual estimates of intensities and their vibrational assignment 
have been collected in Table 1 The maximum value of the difference between observed 
and calculated is ± 2 cm"1 
The occurrence of new bands together with known MgBr bands, and the complete 
absence of any identifiable impurity spectra, suggests that the new bands belong to the 
MgBr The lower state vibrational constants determined here agree with those reported by 
Pun and Mohan [7] and Rao et al [8] for the ground state of the MgBr molecule This 
confirms that the present system of bands is indeed due to the MgBr molecule, and that 
the transition terminates on the ground state 
The B - X system of the three MgX molecules (X = F, CI, I) investigated earlier 
appears in the regions MgF (AA 2630 - 2742 A), MgCI {AA 2666 - 2733 A), Mgl (AA 3850 
- 4010 A) Thus the occurrence of the MgBr brands in the AA 3600 - 3800 A region is 
quite in line with the general trend The (0, 0) band in the case of this system for the 
MgF, MgCI, Mgl molecules lies at A = 2689 A, A = 2697 0 A and A = 3904 5 A 
respectively It can be seen that the shift of the B - X system as a whole and the 
respective (0,0) bands, to the ultraviolet is quite general Similar behaviour is shown by 
their ground state vibrational frequencies also The summary of the vibrational constants 
of all the observed systems of the MgBr molecule and shown in Table 2 
Table 2 Vibrational Constants of the MgBr Molecule (cm-1) 
System 
A2f/V2 X21 
A2nV2 - x2i 
B21 - X2I 
Czl -X21 
D21 - X21 
E2//V2 X2I 
E2//2f2 - X2I 
F21 ~ X21 
G2n2l2 - x2i 
Region (A) 
/A 3659-4033 
/U 3659-4033 
/>; 3600-3800 
>/ 2540-2720 
?, 2085-2125 
A/ 2060-2125 
/>; 2060-2125 
AA 2035-2075 
/A 2045-2080 
voo 
25775 0 
25885 0 
26924 0 
39285 9 
47499 9 
47828 4 
47998 6 
48575 5 
48819 9 
<>e 
393 9 
394 0 
357 0 
271 9 
386 6 
400 1 
400 1 
408 2 
421 4# 
<i*'e 
2 04 
2 00 
2 00 
5 20 
0 63 
1 28 
1 28 
1 03 
-
"• 
374 14 
373 4 
374 2 
373 2 
375 2 
375 0 
375 0 
376 1 
377 2 
"•*. 
1 47 
1 20 
1 2 
1 34 
1 80 
1 74 
1 74 
2 33 
2 16 
Remarks 
Ref [7] 
Ref [7] 
* 
Ref [6] 
Ref [8] 
Ref [8] 
Ref [8] 
Ref [8] 
Ref [8] 
* Constants suggested by authors, # M31/2 value 
The normal state electronic configuration of Mg and Br atoms are given by 
12Mg Is2,2s22p6, 3s2 1S0 
35Br 1s2, 2s22p6, 3s33p63d10, 4s24p6 2P^2 
A new band system of the MgBr molecule 1527 
Considering the separated atom model, the ground state of magnesium is 'S0 while 
bromine has 2P3/2 The resulting molecular electronic states are 2n, 2I The ground 
state for MgBr molecule has been established as a 2^ [9] arising from electronic 
configuration (wx)4 (xcrf Thus the optically allowed features of spectra (single headed, 
sharp, and well developed bands) support the assignment of B - X system to the transition 
2 v - 2S This conclusion is analogous to the B - X system of isovalent molecules like 
MgF and Mgl [9]. 
Acknowledgments 
The authors are thankful to Prof. M M Joshi for the fruitful discussion One of us (Renu 
Singh) is grateful to the UGC, New Delhi for the financial assistance in the form of JRF 
(NET) 
References 
[1) C M Olmsted Z Wiss Phot 4 293 (1906) 
[2] 0 H Walters and S Barratt Proc Roy Soc A118 120 (1928) 
[3] F Morgon Phys Rev 50 603 (1936) 
[4] R E Harrington Ph D thesis University of California, USA (1942) 
[5] M M Patel and P D Patel J Phys B At Mol, Opt Phys 2 515 (1969) 
[6] B R K Reddy and P T Rao Current Science 39 509 (1970) 
[7] S N Pun and H Mohan Current Science 43 442 (1974) 
[8] V M Rao, M L P Rao and B R K Reddy J Phys B15 416 (1982) 
[9] R Yamdagni Ph D thesis, Allahabad University Allahabad, India (1964) 
[10] Kaley A Walker and Michael C L Gerry J Chem Phys 107 9835 (1997) 
[11] T Hirao, B Pinchemel, P F Bernath J Mol Spec 202 213 (2002) 
[12] K N Uttam, R Gopal and M M Joshi India J Phys B66 379 (1992) 
[13] M N Saha, N K Sur and K Majumdar Z Phys 40 648 (1927) 


A New Band System of the MgBr Molecule

Deo, B B

Mishra, P K

Calculation of the Masses and the Running Masses of the Quarks and Leptons from Electroweak to Supersymmetric Grand Unification

Indian J PAyj.82(ll), 1599 (2008) 
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80 Years Ago - the Discovery of the Raman Effect at the Indian Association for the Cultivation of Science, Kolkata, India

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A New Band System of the MgBr Molecule

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